interesting idea

Although I can imagine agents/players trying their luck with it.. i.e.

Said home grown player is valued at $20m on the market, so home teams only counts $10m against the cap.

Agents will say that's a barging for the team so pay us $24m as you'll still only have to cap count £12M.

Whereas if you try to replace with a player valued at $20m from another team, the whole $20m will be cap counted!