Nothing affects current. ADV affects projected.
Most players are close to fully developed by their 4th/5th seasons. You won't see improvement by more than a point or two. If you're trading for 3rd year players, they should be nearly BL-ready. They will only have moderate improvement. That's why ADV is only needed if you're trading for 2nd year players. You just don't know with them.
Now there are exceptions to the above. But I'm not dropping 20m into ADV for exceptions. Trading for prospects has always been tough in my worlds. Users overvalue their players and especially their prospects.