Viscosity: ND11 Compressor Oil vs. Interdynamics Compatible Oil

Hello:

Compressor was inoperative (noisy when forced to operate for a moment during the diagnostic process) on my 2006 Prius and I just had it replaced with a used unit that had 55K miles on it. ND11 was quite expensive so I bought an after-market ND11 compatible oil (Interdynamics HYB-1 from here after reading Priuschat forums and forumers' experience with these).

During the recovery and evacuation, total oil recovered from the compressor and the system was ~1.5 oz and total refrigerant was 16.1 oz. To be on the conservative side, the mechanic added approx. 1.75 oz of the HYB-1 oil with 16 oz of new R134a. He measured the viscosity of the recovered oil and it was nearly 3x of the new oil being added. He did not find any debris or undesired stuff in the system so we decided to not change the receiver-drier.

Now, I am trying to determine if there is data on the viscosity of ND11 and how it measures to the HYB-1 or SuperCool products that are available. I understand that as the oil is used, it becomes viscous. Was that the reason for the old oil to be thicker? If so, have we added enough to satisfy the 4 oz required?

The HYB-1 sticker says that it is compatible with ND11. However, now that I probably have a mixture of ND11 and HYB-1 in my system, should I expect any issues?

A/C is operating fine as of now and compressor is quiet.