Once you touch one of the smaller flags with your infantry, the retreat button is unlocked for defenders and they can use that to replenish all of their resources, unspent ones will be lost though. Plus defenders get 1 mp payback per second during whole game, attackers get 500 mp every 3 mins but no payback.

Payback (light yellow color on income UI) is a secondary income, from units you have lost, full price is repaid to you, rate depends on current cp taken, below 25 is 1.5 per second, below 50 is 1.3, after 50 it goes from 0.8, 0.5 at ~60 or so and down to 0.2 at ~90 cp, those are hard values, NOT % (yeah devs of this game are this bad), so even if you are playing with 1000 max cp after your whole team left, you are still going to have 0.2 mp per second after you hit 90 cp, even though it would be just 1/10th of your cp pool and you wont get increased payback rates due to missing teammates, so even a single missing teammate is going to put your team behind in resources during a long match.
By the way officers cost negative cp value - they reduce your active - taken command points, thus granting your more mp in the long run if you keep them alive and stay below 50 cp, officers are limited to 3.

Max mp is your max mp pool you will be able to reach, by 25th min in vanilla (different timers in robz and other "gamemodes" it adds), i.e host set mp to 6k, thus you wont have more than 6k mp available: spent or unspent. Unspent MP is displayed as orange bar, payback to receive in light yellow and part of the income bar will be blank - thats your mp to receive till you reach 25 mins in vanilla or 35 mins in regular robz assault zones (diff timer for doctrines), after that there is only payback as your income.

Ok, thank you very much for the response I really appreciate it.