Not sure how to upload the spreadsheet, but here's a verbal walkthrough of what it does:
Section A works out the "fair" total IXPs for each player. You tell it the previous "fair" value, the amount of "monetary" treasure given out and the number of players, and also enter in the items you gave out during the adventure (one level 9, one level 8, two level 7, one 6 and one 5, for example, in my current adventure for 7 PCs). The spreadsheet has a lookup table where it can turn item level into value in IXPs, and does so. Then it adds in the money plus the values of those items and divides the total by the number of players, adds that to the previous share value, and the result is how many IXPs worth of treasure each PC "should" have.
Section B lists the items the party owns down the left, and has PC names across the top. As I add an item, I write in the name and its level (which again is looked up to get a value). I then put a "1" at the intersection of the item and player. (Or 2 if they've got two instances of it, or in one case 0.5 since the item's considered shared by two PCs, etc.) The spreadsheet then adds up the total value of each player's actual items owned, displays that, and also subtracts it from the "should have" value calculated in section A. The result is how many IXPs each player has "banked" which they can use to spend on new items.
If someone's in the hole, they can't requisition items - can't even have someone make one with Enchant Magic Item. More commonly they seem to hover around about the value of one item of roughly their own level, in the bank, and so when items come out the ones who had the most saved up will tend to get the Level+4 and Level+3 items, and drop into the hole. And so it continues.
After an adventure you simply write the new "fair share" value into the "old fair share" space and clear the rest of Section A, and it's ready for reuse.