Preserve due times when changing due dates

When I want to assign multiple exercises in a specific order,  I usually assign them sequentially by due time such as 22h00m, 22h01m 22h02m and so forth. 

If i need to change the due date, it changes all due times as well, "ruining" my sequence of exercises :)

It would be nice to have a tick or something that would allow me to change the due date without altering the due times. 

Thank you. :)