Atletico Madrid took the unusual measure of offering more than the release clause in their attempt to sign Joao Felix.
On Wednesday night the Spanish club tabled a £113m bid for the highly-rated Portuguese teenager, £6m more than his release fee.
Essentially, the Spanish side are trying to persuade Benfica to allow them to pay in installments.
They are offering an extra £6m for what they hope will be accepted as a staggered payment plan over a longer period of time.
Diego Simeone's side are on the cusp of recouping £107m for the sale of Antoine Griezmann as Barcelona are expected to trigger his release clause next week.
But despite the precise amount they would have to pay for Felix, the club want a more long-term repayment strategy.
Benfica confirmed the firm offer from Atletico on Wednesday and informed the Portuguese stock exchange, explaining the details and telling them they are taking the bid under consideration.
If the move is completed, Atletico will have seen off interest from both Manchester City and Manchester United to get their man.
Felix is one of the most promising young talents in European football.
He scored 20 goals and contributed 11 assists in 43 games for Benfica last season and his current deal expires in the summer of 2023.
The 19-year-old also made his Portugal debut in this month's 3-1 victory over Switzerland in the UEFA Nations League semi-final.