Maintenance related cancelation

Hey,

In the recent days, many of my flights got canceled because several of my aircraft's condition dropped below 50%. What confuses me is that I have more than enough money every day and each plane (doing 6-8 hops daily) got enough maintenance window, around 5-6 hrs daily. Does the plane age affects how much maintenance time needed? Fyi, my MRO is African Maintenance. Is there any option to do like an intense maintenance for the whole day? I'm losing money from this cancelation.

Thanks!

A Screenshot of a flight plan would help.