I am more than serious. Quantity is the worst choice for Muscovy because existing bonuses are huge. How can 150k can be spent early game? Why would I want more manpower than I can spend in any war? Quality of troops is always an issue with early game Ottomans or mid-game Austrians or French. It makes sense if you love sieging with 15k infantry stack on Finnmark which I don't do.
Manpower of this quantity changes the game. For instance now you have to fight rebels. This will tick your manpower down while at peace. If you take quantity then you can drop LA at will and just eat the rebels in your giant manpower pool.
I've seen manpower pools of 150k die regularly enough in this game.