Understanding Oscilloscope voltage rating

G'day Guys,

I am trying to make sure I correctly understand the voltage ratings of my oscilloscope before I blow something up.
My scope is an Owon SDS210S
https://owon.com.hk/products_sds200_series_digital_oscilloscope

The voltage rating of the scope is 400V
scope.png


If I understand this correctly:
The voltage must not exceed 400v total including any and all AC + DC components.

Then there is the probes:
The OW3100 probes that come with it state:
"1x ≤ 200Vpk 10x ≤600Vpk"

If I understand this correctly:
Under 200Vpk I can use the probe in 1x mode.
Between 200Vpk and 600Vpk I can use 10X mode.

I assume Vpk here refers to the total voltage of any and all ac + dc components.

So assuming I have all of the above correct:
As long as I keep my probes in 10x attenuation I can safely probe a tube preamp with a 265Vdc B+ and its power supply with its maximum raw B+ of 330ish Vdc.

Have I missed anything?