Good point. But more important is that Federer takes the records for most weeks in top 2 ,3 5 etc. Top 10 will be hard with 5+ years to go.
I saw a list for most weeks in top-2, top-3, top-5 and top-10 on Wikipedia not long ago, but it has since been removed, for some reason. Does anyone still have it available? Anyway, from memory Ivan Lendl had 403 weeks in the top-2. At the moment Federer is in his 384th week, so if he can manage an additional 20 that will be enough for this record. 20 weeks from now takes us to Jan 14th. This is not only possible, but very probable indeed.
As for top-3 I remember Connors having well over 200 weeks in 3rd position, so that is going to be more difficult. And since Connors also had a lot of weeks as #4 and #5 this is not a record that is going to be broken anytime soon. Something to look forward to, then