How much can numbers be manipulated?

I sold my S Corporation last year, worked as an employee of a company and worked as a 1099 contractor who paid me personally. I've been back and forth with personal and business returns, attempting to find the maximum return amount for an earned income credit. I've done most of this, but don't know for sure what the Cost or other basis plus expense of sale means on line 21 of form 4797. And if my corporation grossed $30,000, is that the maximum depreciation I can transfer to my personal income between my wife and I? We are the only shareholders. I have other ambiguities, but those are the main ones. Thank you in advance for your help!