Howling:Future anniversary

I have just thought of a problem doctor who clearly celebrates its anniversary every 10 years the 3 doctors was 10th the 5 doctors was 20th it was on hiatus during the 30th and 40th anniversary then we had the day of the doctor for the 50th but what about future anniversary we have lost 4 doctors and matt smith is going to be 40 when its the 60th peter capaldi will be 65 matt will be 41 david will be 51 and paul mcgann will be 63 the only way I can think around it would be what the 10th says to the 5th that the two of them together shorted out the time difference but I'm not sure