Hi, Sya,
Every month that goes by without signs of progression definitely shifts the balance away from ALS, so I'd basically ask the neuro to lay out the specifics that she's basing her diagnosis on outside the bulbar region. As you know from reading out PLS forum, it's not unusual for UMN only symptoms to spread very slowly, over time periods measured in years, rather than weeks or months.
I'm guessing that the neuro is repeating the EMGs every six months in hopes of catching the LMN problems she's expecting at the subclinical stage. Let's just hope and pray for another clean EMG so we don't have to check off anything else on the ALS checklist.