I ask myself this. Why would anyone want to put such an outstanding clock of great quality such as this on ebay. Study the photo of the train and you can see all the wheels have been hand pierced. I’m assuming all photos were taken before a complete overhaul took place as the plates are very stained. It’s a little overpriced.
200s slow per day is not massively slow. That's only three minutes, and probably within the range of the regulator if the hairsping has relatively few coils (since indexing makes a relatively bigger change to the hairspring length).
Bear in mind that often watches run slower once cleaned if they have previously been regulated when not running perfectly. For example, if the hairsping was slightly sticky when regulated previously, it would be regulated slow to compensate for the hairsping vibrating too fast due to stickiness.
The watch should run roughly to time without any oil.
40 minutes slow per day is a serious error, and assuming the balance is swinging with reasonable amplitude, I'd expect it to most likely be an issue with the resonance of the balance (hairspring, indexing, balance weight) or slipping in the motion works (cannon pinion). If you are sure that the timegrapher is set to the correct beat rate, then it would seem to point at the balance.
Did you try what I suggested by inspecting the pallet fork shake while the balance is held 90 degrees away from rest? I casn explain in more detail if required.
I'd also check the basic things like the the impulse jewel (is it loose, broken?) and generally check the safety dart on the pallets doesn't look bent.