Would it be possible to change an on-going C check to also include D check? Naturally, the difference in costs would have to be paid, as well as the maintenance time lenghtened (with even a couple of extra days when compared to pure D check). This would help when automatic C check triggers on planes that are just about to go into D check.
Also, this request is related to this one (https://www.airwaysim.com/forum/index.php/topic,27849.0.html).