Wait, these figures are all over the place. Dortmund never demanded 120 mil pounds last year (thats nearly 140 mil Euro), they wanted that in Euro.
Same with the numbers this year. If Dortmund would want 80mil + 20mil pounds, it could total to around 115 Mil Euro, which is a higher demand than anything reported from reliable sources thus far. The sources are similarily consistent in the sum that is needed to satisfy the gentlemen agreement between Sancho and Dortmund this year as they were last Summer. The target point is 100 mil Euro, some report that Dortmund would accept easily to obtain add ons as part of the deal (models like 90+10 or 95+5 circulate), other state that they want it as fix sum.
If United would be already ready to pay 80 mil pounds, simply slapping 5 more mil in realistic addons on that down the road would probably already do the trick.