Words and stuff
I would agree with you, except the howitzer fire isn't strong enough to really warrant the cost or effort. For your 100 munitions you only get three to six shells from a pair of relatively ineffective howitzers. The ability would be almost useless if not for the air burst shells from anvil tactics.
You get the same problem with the sexton, except fortunately you can drive the carriage close enough to provide somewhat accurate fire.
For a doctrine that's all about artillery, the artillery firepower provided is rather mild. I think you'd be better off just burning 100-130 MP on infantry section casualties running them up to things to throw the flare in person. You get to use the same howitzers, but for less than half the cost and twice the ordinance fired. You could choose a more useful doctrine and still make full use of your base howitzers with just a bit of extra effort and investment.