micsig DP10013 input voltage

[thedoc298]

The specs for the DP10013 are

Maximum differential test voltage (DC+ACPK-PK): 130V (50X), 1300V (500X) from their site

So does that mean 130 volts Pk to Pk or 65 volts Pk which in turn would be 46 volts rms            so on x50 we have 46 volts rms max

same 1300 PK to PK = 650 Pk or roughly 460 volts rms                                                            so on x500 input is 460 volts rms max

So why don't they state it like that...? Or am I all screwed up..?

[m k]

It's differential so potential difference.
Forget grounds and signal shapes.