Barnesy would tell you it's considerably less. Everyone just picks a number that works for their agenda I reckon.
£10m will be the top end which will include clauses such as getting promoted etc. - this makes sense, Spurs want their money back at least if he's a success.
But there were rumours that it was as low as £3m upfront as well. I'd expect that we're structuring all of our deals in a way that the bigger clubs get more from us if the signings are successful. My unsubstantiated guess is it was structured something like this:
£3m upfront fee.
£2m in installments over the next 2 years.
£2.5m if we get promoted whilst he's here.
£1m after he makes 50 appearances.
£1m after he makes 100 appearances.
£500k when he pulls on an England shirt.
20% of any profit we make on him.
So Spurs are guaranteed £5m, they'll get £7m if he's a relative success, the full £10m if he smashes it and a little extra if we sell him on for more than £10m.
We get a player that had previously excelled at this level (and cost Spurs £10m) for half of the price, with even less upfront. If he becomes an established Championship player then we pay them a little more and if he takes us to the Prem then we pay the maximum.
In my opinion, a winger playing 100 games in the Championship is likely to be worth more than the £7m he would have cost us to that point. A winger playing in the Prem will be worth more than £9.5m and an England international worth a lot more than £10m. Given that he's only 21 as well, it represents great value and an ambitious purchase.
I like your style! Are you KS by any chance?