Data Hand-down

Reet, I have a problem i have been pondering over for the last hour or so and im not sure the best way to do this! Its slightly tricky to explain so bare with me!

So I've made a Software Licensing Database which tracks licenses etc.. Its based information provided by another company which handles all my companies data handling etc..

Ok so in this database it tracks all installs and compares them against licenses. But this 3rd party company doesnt make life easy and sporadically buy licenses thus there's are always licensing issues here and there.. hence wantign the db to keep track. However rather than having a simple 10 licenses, 10 intalls for abit of software, they have created an entity called a Delta which is hand-me-down licenses. i.e.

Adobe Acrobat Pro 8:
100 Licenses | 50 Installs | 50 License Delta

Adobe Acrobat Pro 7:
25 Licenses | 93 Installs | -18 License Delta

So as you can see the Delta is Licenses available for lower versions & editions of software. So where I get these reports on a figures basis my boss wants me to physically give each install a license. Thus thats me breaking down a number of License into a singular form and assigning it to a specific person. Which is all done thats easy enough my problem is Incorporating the delta for that piece of software. So above as you can see for Adobe Acrobat Pro 7 I can happily assign those 25 Licenses to 25 of the 93 people but I dont know how to reference the 50 Delta Licenses on Adobe Acrobat Pro 8 to the remaining 68 people.

Of course the example I have provided makes it seem not to difficult but you have to remember I have about 60 different versions of Adobe Acrobat, they have multiple editions (Pro, Standard, Corporate, blah blah...) Baisically I cannot see anyway of writing abit of VBA giving each bit of software a Hierachial order in which to refer to.

The best possible way of doing this I can see is creating an alternative table which I will have to manually go through the 23K bits of software and define which bits of software are higher up the foodchain & eligible for a 'Delta License'

Any help is much appreciated!

Cheers