Board Thread:Questions and Answers/@comment-29666298-20160913153732/@comment-232062-20160913170620

Yea, by using your daily improvement quest which refunds a single screw and improving a T21(s) you can substantially reduce the screw cost when compared to outright maxing the T53.

To make sure you don't upgrade something you didn't want to, it's pretty easy... keep your gear locked.. The T21(s) needs 3 unlocked 7.7machineguns and the T21(s) is's self needs to be unlocked, as long as you make sure all you're equipment is locked it would be impossible to upgrade. Normal improvements do not require the item being improved to be unlocked (the items consumed do need to be unlocked obviously), only upgading and converting require the main item to be unlocked. Basically whats happening is the item being upgraded or converted is being taken away from you and replaced with something else, and that would be impossible if that original item were locked, when you try and upgrade or convert with locked items you'll see red error text in Akashi's arsenal or a red text popup in the quest page telling you to unlock the items..

As far as the Kaku quest chains being buried behind week/monthlies... I dunno, I did both chains and all the conversions straight away when the quests came out so I don't know or can't recall. Sandbox/Aircraft Conversion Flowchart (wikiwiki ver.) judging by that flowchart, as long as you do or have done Bm6 & 7 for this month and unlock A61, you should be good to finish the questchain at your leisure.