The Sané money, and (more importantly) the profit on sale, will be in the 2020/21 financial year, which ended in June. But that doesn't really matter because of the way FFP works, with figures aggregated over 3 years.
Also people don't really understand how the whole financing of transfers works.
In a normal year, City would generate around £125m of spare cash from our normal operations. I cant be certain, as we don't publish a separate cash flow statement for the club, only for CFG. But a basic calculation means it will be around that figure. Then incoming transfer fees are added to that cash pot, most of which will be used for paying for transfers in.
There's more that needs to be taken into account on top of that. We may show a book profit on players we sell. If we take Leroy as an example, he cost us £40m (to use a round number) and let's say we sold him for the same amount. But as he'd been here 4 years, we'd have shown £32m amortisation, making his book value only £8m. That means we can book a profit of £32m on his sale. That's not cash but it can be added to the pot as it will cover £32m of amortisation and wages for an incoming player or players. I know we laugh about the Coutinho money, but that's how it works.
And then there's the amortisation and wages saved by him not being here, which is £8m plus whatever a year's wages was for him. Let's say that was £7m, which means we've got £15m extra to play with in that year. That alone covers a years amortisation for a £50m player on £100k a week.
People ask why we bother with an academy when we seem to sell most of the player. But while we sell them relatively cheaply, and they aren't on big wages, it's all profit so selling a couple of decent academy lads, like Harrison & Angelino, brings in £20m profit and that's a full year's amortisation on Grealish. Do similar every year with a few Academy players and that's the Grealish fee fully covered.
I've said this before but in the summer of 2017, when the media went on and on about us spending something like £200m gross and £120m net, our player costs (wages + amortisation) only increased by £8m that year. That's because of wages and amortisation off the books for players we sold or loaned out. That's why net spend is a completely useless comparison.