Commissions were different back then. I worked part time selling computers around 1990 and a little earlier, margin on computers was moving down, but was as high as 50%, I recall it moving down to 30% and stabilising there for a while. I don't remember software margins, but it could have been about the same. I used to get 50% of the margin as commission.

When I sold Windows 2.1 at Egghead Software, my spiff was an extra 30% for the first month as a promo. I always assumed that was a loss leader by Microsoft to push extra copies on release.

Hey, and now Apple and Google have set it at 30% again!