Well, a little bit of a simplification. I don’t want to insult you, for all I know you may have been brewing for years and hundreds of batches. But, both the aerobic (using O2) process and anaerobic (without O2) process happen at the same time. However, in the early stages of fermentation there is more aerobic fermentation until the available O2 is gone. BUT… the bubbles being produced in your airlock are not O2, but CO2- carbon dioxide. Anaerobic fermentation yields predominantly CO2 and ethanol.
The most important point is that the yeast don’t read. They ferment at their own pace. Granted it mostly depends on yeast pitch rate, nutrient level, and fermentation temperature. But sometimes our little friends just do things the way they want to, not the way we expect.
Then, as sneezles suggests, without taking a SG from each BmB there’s no way you’ll know if one batch was at 1.035 and is done while the other batch started at 1.065 and still has a little further to go. And finally, personally I don’t rack to a secondary (when I do) until I know the fermentation is completely finished. Don’t remove an actively fermenting beer from the yeast unless you have some overwhelming need to slow down the fermentation.
If it were me, I would probably take a current SG from each to see what I’m sitting at. And of course I’d RDWHAHB and wait another week or so before even thinking of what to do with it. Good luck. I’m sure she’ll be fine!