After I had posted my last post I realized that might have been the error I was making. The wording in the DMG is a bit obtuse, but now the whole process does make a lot more sense as it seemed AC and attack bonus were causing everything to be a lot more swingy than it needed to be. It also looks like the correct process will be a heck of a lot simpler and intuitive.The attack bonus is +10, you have that correct. However, this is how the affects the CR:
1) Calculate DPR: in this case DPR of 48 equates to a CR of 7; which has an expectyed attack bonus of +6
2) Determine expected attack bonus based on DPR CR (7); which in this case is +6
3) Calculate the effect of a different attack bonus on the Offensive CR. For every 2 difference in attack bonus adjust the CR by 1. So we take the giants actual attack bonus of 10 and subtract the expected bonus of 6 given a a result of 4, then divide this by 2, resulting in an adjustment of +2 to the CR
4) Adjust the DPR CR (7) with the attack bonus adjustment (+2), resulting in an offensive CR of: 7 + 2 = CR 9
In other words:
You look at the DPR column first ( CR 7), and then adjust that CR by the difference in the bonus (+10, actual, - +6, expected) divided by 2 (round down).
You do not subtract the attack bonus CRs from each other as you did, you subtract the actual bonus (DMG pg 274=275):
"Now look at the attack bonus suggested for the monster challenge rating. If your monster's attack bonus is at least two points higher or lower than that number (referring to the attack bonus suggested), adjust the challenge rating suggested by its damage output up or down by 1 for every 2 points of difference."
*bold underline for emphasis and italics added by me
I hope that helps: FYI, I made the same mistake at first too, I even had a spreadsheet made that calculated CR they way you thought before I realized my mistake
Thanks for the help, and I'll get to correcting what I've posted so far!
Sent from my VS987 using EN World mobile app