Okay the assumptions are piling up here and they may prove to be correct but they may not. With any transfer even ones that look quiet good at the outset a 100% loss is always available, which is why Jordan Ibe is so very relevant here. Against this Sheffield United have capped any profit they make from the deal at around £10.5m.
What makes it worse is that should things not work out and Sheffield United end up selling at a future date for £10m Liverpool have £1.5m of that fee and Sheffield United are nursing a loss of £13m
The other assumption is there is a market outside the English top flight that will pay £10m plus for a player who hasn't confirmed his early promise which cushions the downside, I know that place used to be called the Championship but I suspect that might not be case now or even in the future.
True, I did make some assumptions, but only in response to your absolute that it cannot work out for Sheffield United. We are also assuming the numbers are accurate. I suspect the buy back has some terms and restrictions, and I imagine the sell on is only on any profit.
The part missing when talking about capped profit is the value he has while at the club which is harder to quantify but could be huge if he players a big part in the clubs development.
There was discussions about us paying £5m for Grant, in a situation where he goes back to Huddesfield if he goes down and people were ok with that. Well I genuinely feel that you'd get £10m for Brewster in two years time, even if it goes terribly. So consider it £5m a year for a two year loan at which point you might cut your loses or if it goes well you may see a player go back to Liverpool and make some money.
If Watkins is £28m, and Grant is £18m. This isn't a terrible deal for a lad who is streets ahead of where either of those were at 20 and has always been incredibly highly rated.