You need the work permit to carry out any work in Thailand. The non b ( 90 day) you currently have does not allow you to work, just allows you to obtain a work permit that, in turn, allows you to work.
Even with the initial non b, you shouldn't be carrying out any work until the Work Permit is in place.
If your company is unable to furnish a Work Permit then you're done. You'll need to find another employer.
yes. I know all that. I'm asking for recent experience from Indian passport holders. Not sure I could have worded it more clearly. And for visa exempt it's 20,000 and 40,000