Pence or Grassley?
Pressure on Pence
What's with the original "we don't expect him to be there" quote?
Pence may very well wish to not preside over the count. It has happened before and it would relieve Pence from having to take a stand for or against Trump.
For discussion, please see Pence is in the Limelight as Trump Increases Pressure
There's another way Grassley would preside.
If Trump resigned before the count, Pence would become president, and Grassley, as the Senate president pro tempore would preside.
This appears to be a moot point because I do not expect shenanigans from Grassley.
But what if it was Senator Ted Cruz instead of Grassley presiding over the count?