Yes, we support this and it can easily be implemented. We're very customizable here and give our users some options to choose from, because like you said, it can be a difference between a win and loss.
fleaflicker.com
We support:
Points Allowed=All points (what the opposing team's final score says)
Offensive Points Allowed=FG, pass TD, rush TD only
Special Teams Points Allowed=Punt/kick return TDs and all conversions (both XPs and 2-point conversions)
Offensive Plus Special Teams Points Allowed=The sum of offensive and special teams points (i.e., everything except for safeties, INT returns, fumble returns, and blocked kick returns). Most leagues will want to use this rule