Salah left Liverpool as a free agent after his contract at Anfield expired, sparking speculation over his next destination, with the Turkish club among those to have held talks. Adali explained that the transfer appeared close to completion before the demands from Salah's camp increased.
"Mohamed Salah has given his approval for this transfer. His agent also gave us a positive response to our offer in the first stage," Adali said.
"Afterwards, his agent raised his own commission to 35%. It is not possible for us to accept a rate like that. We don't believe Salah is aware of these figures."
The comments suggest talks between Besiktas and Salah's representatives remain unresolved despite significant progress having been made on the broader terms of a deal. Salah's agent, Ramy Abbas, has continued to tease developments in the player's situation on social media without confirming a destination, fuelling speculation that a move to Turkey, while still possible, is far from certain.
Salah made 41 appearances for Liverpool last season, scoring 12 goals and providing 10 assists, before representing Egypt at this summer's World Cup, where the Pharaohs reached the last 16.
Should the transfer eventually go through, it would represent one of the most high-profile free transfers in Turkish football history, with Besiktas hoping to use the move to boost their standing domestically and in Europe next season.
Besiktas had reportedly reduced their initial salary offer expectations after Salah's camp signalled some flexibility, with the 34-year-old's representatives said to have travelled to Istanbul in recent days to continue discussions.
Adali's comments suggest the two sides remain some distance apart specifically on how any agent fees would be structured, even if personal terms between the club and player are close to being settled.
Galatasaray and Fenerbahce have also been credited with an interest in Salah, according to reports in the Turkish press, though neither club has confirmed formal talks.
Besiktas fans have made their desire for the move known during recent unveilings of other new signings, chanting Salah's name in anticipation of an announcement that, for now, remains unresolved.