Just as an update:
Having gotten sidetracked onto a different project at the end of yesterday (darn multitasking) I've only now been able to verify the answer:
((((StartingDay - FindDay + 6) Mod 7) + TotalDays) div 7);
Rompel was correct, though in the Pascal implementation the "Div" makes a Trunc unnecessary.
Thanks again to all, I'll feel much better about the way this works now. (The existing solution built up an array in global memory by the slow method. I didn't care for this as it really divorced the computation from the usage as well as requiring an unnecessary global variable).
_________________________
-Jeff
Rome did not create a great empire by having meetings; they did it by killing all those who opposed them.