Back in January I solicited guidance on how to get the screws loosened on my mast step.
I'm pleased to report that after a winter of soaking the screws in WD-40, and with the combination of an impact driver, a 5 lb sledge, a propane torch and a 2 x 4, the screws loosened sufficient for me to beat on the step with the 2x4 and move the mast step back the required 1/8". The step is now OD compliant!

Thanks to all for your suggestions