After playing with partedUtil getptbl and getUsableSectors, it seems like I expanded the wrong partition.
I was not in the right view (GPT) but I was under the (MSDOS) where it did not tell me what partition was what:
So, after using the Usable sectors, I found out I had some more usable ones and extended Partition 2, instead of the vmfs 0 I needed.
Seems like partition 2 here is "VMKcore".
How bad is this f*ckup and how can I easily undo this? (details pls).