First off this thread belongs in the house rules forum vice the rules one since it specifically addresses a house-rule.
Second - I would never use the house rule. It just doesn't make any sense to me that suddenly a character has learned more (that is what ranks reflect some sort of learning while ability mod reflect an innact natural ability to do something) 2 years ago (just using the time to reflect levels even though there is no direct correllary).
Third - concerning the reason that an abiity increase to CON gains hit points retroactively is that IMO HP are a reflection of the potential a character has for taking punishment. Note this is not the hit dice (which can be related to training if one wishes) but a natural toughness. So if a character has gotten tougher than his natural limit has increased.
Forth - using retroactive Int increase will likewise open the door for things like more spells for a 1st level wizard and the like.
Bad precendent IMO.
Second - I would never use the house rule. It just doesn't make any sense to me that suddenly a character has learned more (that is what ranks reflect some sort of learning while ability mod reflect an innact natural ability to do something) 2 years ago (just using the time to reflect levels even though there is no direct correllary).
Third - concerning the reason that an abiity increase to CON gains hit points retroactively is that IMO HP are a reflection of the potential a character has for taking punishment. Note this is not the hit dice (which can be related to training if one wishes) but a natural toughness. So if a character has gotten tougher than his natural limit has increased.
Forth - using retroactive Int increase will likewise open the door for things like more spells for a 1st level wizard and the like.
Bad precendent IMO.