The Tech-Aero shows two identical packs. In that case the load is evenly split as they show. And that is a parallel arrangement. Regulator or not has nothing to do with the connection type. If two packs are connected to a single load then they are connected in parallel. So plugging into two separate ports on the RX or even using two packs plugged into a "Y". All are parallel connection arrangements.

If the capacities are not the same then the load will be different on each pack. Ohm's Law requires this since they are at the same voltage on the RX bus. This is why I asked the OP what he actually put back into the packs. That is the only way to know what he used from each. The resting post flight percentages read off a meter or the charger are not as accurate as knowing the actual capacity replaced.