1) Depay has WC experience, Tielemans not even selected for the Red Devils
2) Depay has a role in the team that is much more decisive for assists and goals so that also highers the price
3) The top players in the Dutch league always go for more cash then the once in Belgium.
4) Depay has played consistently on a high level for 2 seasons now, Tielemans has had his dip in form this year.
And I agree he should go for more, but that wasn't the question, the question was what I think he has to cost.