It'd behoove Porter to take the highest bid possible because the Wizards will likely match anyway.
Free agency works based on priority levels, thats how the dominoes fall every year.
Bogdan is not an A priority, players like Porter, Gordon Hayward and Gallinari are, proven starters... He's somewhere in the B or C range along with Joe Ingles (who's at this stage better and more proven), CJ Miles, Rudy Gay and Andre Iguodala.
Bogdan doesn't have carte blanche or the sort of leverage where he can make extreme contract demands, Fenerbache will be owed over $1MM for his buyout, his options and negotiating power inside the NBA are still limited, he's not on the Rookie scale but there's still no impetus to overpay him. If he wants the big $$$ you come to the NBA and prove that your worth it in your second contract, thats the way things are structured, I assure you he's not gonna break that mold.
There's a lack of precedent for what you're talking about too, he's in a similar situation as Mirotic years back and will get a similar contract.
To outperform a $10MM/per season contract as a bench player in the NBA you need to be in the running for the 6th man of the year. How many prolific seasons did Manu have to have under his belt to command that type of contract?
to put it bluntly, the Suns certainly didn't appraise him to be worth that, or anywhere near it, they valued him as a trade chip, and not the lions share of the haul..