Up to 1v block difference after swapping 10 modules

Hi folks,

I identified 2 failing blocks and 3 weak blocks in my new used car's traction battery. Not technically a Prius, a 2012 Lexus CT200h with a Prius pack.

I ordered and installed 10 modules from a reputable ebay seller (2ndlifebattery) which arrived at 8v each. They were cycled and load tested before purchase, and appear to be excellent.

The problem is now I still have a voltage difference, even more extreme, but in the other direction. It isn't the weak modules bringing the pack down, it's the 18 other modules being significantly weaker than the new ones! :O

I'm worried about driving around like this and hurting the factory modules. Thinking about getting a Prolong Discharger to cycle the pack and bring the weak but otherwise decent factory modules closer to the new modules. I already have the Prolong Charger and was expecting it to balance the cells but.. it just doesn't? (Ok well to be fair it DID resolve the initial delta SoC being not 0% as it should be, which is great!)

Would the discharger help or am I about to spend $300 on something that isn't going to make a difference. I think it will but I'm looking for an informed second opinion. Thanks.

P.S. I'm also not sure how to parse the fact that the block voltage difference is sometimes as low as 0.1 while reaching highs of 1.3. Worth noting that no codes are thrown when it exceeds 0.3 for longer than a minute.

 

Ideal outcome after using a grid discharger + balance 3 times would be a voltage difference of 0.2 or less. Is that possible, given the factory modules remaining are all decent?