Incidentally, Although I don't keep track of my modelling time (I'd be afraid to learn the answer), I can estimate how much time I spent correcting the Atlanta's hull to suit my taste.
Note that I personally don't bother much with exact dimensions; I work to the 'looks about right' standard and BNT of about 12".
To that end, I was only concerned with removing the oversized armor belt and not with correcting the beam, chine, etc. Later, I added a lower hull (the one included in the later Dragon/DML variants is - and looks - too shallow in draft).

I would estimate 2-3 hours to remove the belts by carving, putty and clean up the hull, and attach replacement styrene belts. Because it's a fairly simple task, I wouldn't be willing to spend too much for a replacement - maybe $10-15. (I know that's less than Minimum wage, but it's only a pastime for me

).
Carving and shaping the lower hull, however, took me 7-8 hours, not including wait times or the research (to find usable line drawings). Carving and shaping, several iterations of sanding and varnishing, adding details in styrene strip, and final painting all spanned several days of work. And I still need to fashion shafts, struts, props, and a rudder (another 1-2 hours).
Because of the time investment required, I would pay more for a nicely-cast bottom, especially if it included the running gear. Better yet if I could buy a
full hull, but I expect that would restrict the manufacturer's marketing options.

Hope this helps,