Excess OASDI, Multiple Employers, One EIN

I moved jobs last year and had OASDI withheld in excess of the cap for 2021. I'm trying to get the money back through my Federal return filing but am having problems with Turbotax not recognizing my issue as a multiple employer situation, as the company I moved to was acting as a payroll agent (Box C Line 2 states "Agent For: xxx") on behalf of my old employer, and thus the EIN is the same.

 

Some background, I was previously working at a corporate holding company, and moved to one of the company's subsidiaries, which for regulatory and legal purposes is a completely separate legal entity. The subsidiary processes payroll on behalf of the corporate entity, however they are again, legally separate, and thus the subsidiary is not going to publish a corrected W-2 for me. Is this an issue that can be resolved by upgrading to PLUS or Deluxe? Or am I going to have to file a separate Form 843?