Switching from Chemstation to empower: What are authorities requirements?

Hi all!
I’m working in a pharmaceutical QC lab and we are preparing the switch form chemstation to empower.
Our HPLCs stay the same (Agilent 1100), we only change the data software. PQ will start in a few days.
BUT, does anyone has experience in a regulated environnemnt of this switch? What do we have to do to prove that using chemstation and empower is equivalent on our analysis (HPLC stay the same->“signal” stay the same). Do we have to do comparative analysis (1 run on chemstation, 1 run on empower on the same HPLC with the same samples for each analysis type???)?
We actually work with validated excel sheets for chemstation results calculations and we want to use the empower calculation possibilities to throw away our excelsheets…
Our actual strategy is to say that signal is the same and the only difference is the software. We want to compare results obtained with empower and “automatic” calculation versus excel sheets…
What do you think of this strategy? Is it enough to convince authorities?
Does anyone have done this switch in a a regulated envireonnement?
What was your strategy?
Thanks all