I guess that this issue (and similar ones) would be solved if you could mothball a construction.
Right now the best you can do is to build it at 25% speed, and I can understand how, even spread over 8 turns, 250 metal, 250 IPs and 2 machines would be too much in the early game !
Also, being able to mothball constructions without cancelling them would help micromanagement in all game stages, though it might make sense that this currently works like this to make you think before you commit to start a new construction..?
Finally, this could be the opportunity to simplify the asset management buttons :
currently the Active/Mothball buttons are kind of redundant with the 25%-100% buttons, sometimes forcing extra clicks (for instance when you want to re-activate an asset, but not at 100%).
This could be the opportunity to "get rid" of both of those : put a 0% button in the Mothball spot, a 100% button in the Active spot.
(Maybe also have more granular controls on the right : 20%, 40%, 60%, 80% ?
This might also help because a lot of asset costs split poorly into 1/4ths, for instance all those asking for 50 or 125 items.
But maybe it would be *worse* because a lot of construction *times* split better into halves or 1/4ths ?
Yeah, never mind about changing the splits, just replace Active & Mothball by 100% and 0% for both new constructions and already built assets...)