So, I'm curious...
Your rules seem to focus mainly on mercenaries with regards to military forces in large-scale battles. How would adapt these rules for a D&D game, which typically revolves around what you would consider to be a "Small Mercenary Team"?
I have an idea for a mercenary group, the "Streukatzen". Which would consist of a network of, effectively, self-contained adventuring groups -- not unlike what would normally called an "Adventuring Guild" in D&D. Each team would have a half-dozen or so specialists (PCs) that could be hired out for less than what it would normally cost to hire an entire mercenary unit, and be used for jobs that don't require an entire company of soldiers... Private investigations, espionage, assassination, sabotage, theft, kidnapping, bodyguarding, scouting, etc.
What sort of rules might you suggest, SHARK, for the larger organization providing training and support to this sort of small unit?
Indeed, my friend, small teams of mercenaries can easily be hired for whatever kind of work required--investigations, extra muscles, urban security, joining the adventuring party on a dungeon expedition, escorting a caravan, and so on.
The Mercenary Team (3-8 members; roll 1d6+2) is a pretty good size, and flexible for almost any kind of potential small-scale mission. Such a small mercenary team would still of course be led by an NCO, and they would answer directly to whomever their employers were.
Small Mercenary Squad Pay Rates (Each member of the mercenary team is paid this rate/week as the base pay required)
01-10% 4 GP/Character Level/Week
11-20% 5 GP/Character Level/Week
21-30% 6 GP/Character Level/Week
31-40% 7 GP/Character Level/Week
41-50% 8 GP/Character Level/Week
51-60% 9 GP/Character Level/Week
61-70% 10 GP/Character Level/Week
71-85% 15 GP/Character Level/Week
86-95% 20 GP/Character Level/Week
96-00% 25 GP/Character Level/Week
Mission Pay Adjustments/Mercenary Company Organization Fees
Small Unit Missions
General Security/Intimidation (Fixed, or moving, traveling, as needed); Add 1-3 GP/Week. Mercenary Company Fee is 25%/week of total team weekly pay rate.
Escort Missions; Add 2-4 GP/Week. Mercenary Company Fee is 30%/week of total team weekly pay rate.
Guard Location Missions (i.e. Guard this warehouse; guard this tavern); Add 1-3 GP/Week. Mercenary Company Fee is 25%/week of total team weekly pay rate.
Caravan Escort Missions; Add 1-3 GP/Week. Mercenary Company Fee is 25%/week of total team weekly pay rate.
Hunting and Killing A Target ("Bring me his head on a pike!"); Add 3-8 GP/Week. Mercenary Company Fee is 40%/week of total team weekly pay rate.
Diplomatic/Court Missions; Add 1-6 GP/Week. Mercenary Company Fee is 25%/week of total team weekly pay rate.
Rescue Mission (Locate, Extract, and Return a Specific Person); Add 5-10 GP/Week. Mercenary Company Fee is 40%/week of total team weekly pay rate.
Retrieve A Specific Item; Add 3-8 GP/Week. Mercenary Company Fee is 25%/week of total team weekly pay rate.
Dungeon Missions; Add 5-10 GP/Week. Mercenary Company Fee is 50%/week of total team weekly pay rate.
Deep Dungeon/Foreign Expedition; Add 7-12 GP/Week. Mercenary Company Fee is 50%/week of total team weekly pay rate.
The small Mercenary Team would typically be hired for 4 GP/Character Level/Week. Especially dangerous or insane missions they would double their rates or even triple, quadruple, or quintuple them. (x2, x3, x4, or x5 base rates of GP/week). The NCO in charge would command a Bonus of say, 25% of his own weekly pay as an additional bonus for his rank and additional experience. Thus, for example, a typical level 5 Fighter Mercenary would make 20 GP/week as a normal salary for most kinds of general work. His Sergeant, a level 6 Fighter, would be making 24 GP+25%=30GP/week as a salary.
I have generally been purposely vague on providing a whole lot of hard "economic" features, because it seems so often that people institute their own economic models. Some are wildly inflationary and advanced, while others insist that a few silver pieces a day makes for an outstanding wage.

Thus, there may be some necessity for a DM to make various adjustments to their wages and so on. Generally, however, the strong guideline is made with the following considerations always in mind when determining the mercenaries expected rates of pay, salaries, and compensation;
(1) Mercenaries are *self-employed* essentially;
(2) Mercenaries are *in demand*;
(3) Mercenaries provide professional skills, knowledge and expertise;
(4) Mercenaries typically do not operate with necessarily the same qualms, sanctions, cultural taboos, or other such concerns that most people from a particular region or culture may embrace. This has generally provided mercenaries with a somewhat *Ruthless* reputation. However, while many mercenaries are often concerned with the law, as well as honour, and may have other personal requirements and restrictions about various missions--generally speaking, mercenaries are a bit more hard-core, ruthless, and less rstrained than others. This reputation for efficiency, ruthlessness, and focused dedication to simply accomplishing the mission and getting a job done--is itself a sort of "benefit" and strong selling point for mercenaries.
(5) Mercenaries, while not rich, nonetheless insist on much higher wages than the typical labourer or even a bodyguard might make; even comparable or higher than well-trained professionals, because mercenaries are well-trained professionals that break people's legs, fight and kill people, and risk their lives in very dangerous battles and missions. If the mercenaries wanted to risk their lives while earning nickels, then they could have just re-enlisted into the ranks of whatever royal army or noble's army in their native land.
Thus, some quick and smooth guidelines for hiring small mercenary teams for all kinds of missions, especially missions appropriate to the needs and goals of a group of adventurers. As far as particular training and support--the employers could ask that whatever mercenaries made available for the mission by the larger organization of the Mercenary Company possess specific skills, for example; all mercenaries on this escort mission of a nobleman to a foreign land for trade negotioations must have good skills in Bluff, Diplomacy, Spot, Listen, and Sense Motive. Otherwise known as "Skilled in Diplomatic/Courtly Environments" The DM would then make sure each of the mercenaries on the team possessed some good skill ranks in the required skills. With gear, the Mercenary Company no doubt has plenty of resources on hand--or it can easily and quickly get them--to provide a good range of specialized gear and equipment for a variety of environments and challenges. Naturally, such extra provisions of equipment and gear would require a considerable increase in the weekly salary for the mercenaries on hired for the mission.
I provided the above table as a quick scale of various qualities and pay demands made within a market for mercenaries, that the DM can easily select from based on what is appropriate for the local economy. Obviously, even in a particular region where most mercenary companies charge say, between 4-8 GP/character level/week, there might be some that charge 25 GP/character level/week. Why might they do this? They might do this because they only want to work for the wealthiest of employers; they may have exceptionally talented leadership or training; or they may have specialized equipment and gear that is easier for them to obtain and equip than others, and thus this allows them to typically be capable of more than other mercenary units. (For example, a mercenary company that provides even its small teams with several potions of invisibility, strength, healing, etc, for each member)
Do these guidelines help, my friend?
Semper Fidelis,
SHARK