What will cost the replace of wooden composition shingles to 3D composition shingles with new 1/2' CDX ply. And felt paper #30 and painted metal dripedge here in southern California city of industry, this has a total of 31sq two story.
Thank you

I wouldn't go with the plywood,but that's just my opinion.I use OSB for many reasons,one being cost of each unit,another is the OSB doesn't peal in layers like plywood does(in time)
Ease of installation as you don't have to orient the plywood face boards grain patterns in valley cuts or ridge pieces,you can make any and all angles without the possibility of grain direction being an issue for moisture run-off.

Costs for the removal and replacement of a 31 square:

What is the warranty on the shingles(that DOES make a difference to the installer,much less purchaser.)

Are you loading this job manually,doing it yourself,hiring this out for a contract by another?Sub-bing this work?

Pitch of the project(8/12 or 10/12 makes for a price difference as someone has to stage off a higher pitch than a walkable one.)

How many valleys/ridges/vents to be installed,chimney flashing to be replaced,any other flashing like roof-to-wall?

Back to you.