The only way I figured it out was using a spreadsheet. Things weren't adding up and it was really bugging me, so I carefully tracked my expenses to date and budget room on a day-by-day basis and I noticed over the course of the season that my budget room was slowly increasing daily because my projected expenses for the season kept shrinking slightly. It wasn't until I posted about it that Markus chimed in that he'd added the split contract thing for that version.
I'll see if I can dig up that thread... found it!
http://www.ootpdevelopments.com/boar...on-markus.html
And you guys were right - this did start in OOTP12.