2011 Prius - Transmission Fluid Advice; changed recently with non-Toyota fluid

Hey all, I'm new here, so don't be too hard on me. Gotta start somewhere!! Thanks in advance for any of your time and advice.

My family has had 5 priuses over the years, all Gen 2, Gen 3. With mechanic prices the past few years, I started doing a lot more car, tractor, machine maintenance for the family across the board, including my own Prius. The Toyota dealer recommended I change the transmission fluid at 91 K, so I went for it at next oil change (97K). That morning, the small town our family's farm is at (where I was doing my oil change, blah blah blah) didn't have Toyota ATF WS I could find anywhere. So, I just bought some bottles (I think it was Castrol....??) of ATF that, per the manufacturer's description on the back, met the Toyota WS cert. Changed the fluid. I felt so accomplished, especially saving the money changing everything myself.

Naturally, my heart sank when I began reading threads on here months later saying, "Why would you not just use the highly recommended Toyota ATF WS?" Is it that bad to go with the non Toyota ATF WS? It's not like I was against the ATF WS or did it to save money. I just didn't have immediate access to the Toyota fluid, which I figured would be more readily available. So, I just used something compatible, thinking like...well...engine oil. Formulated for the cert I want should be good, right?

So, what do I do? It's only been about 4,000 miles on the non-Toyota fluid.
a) Go with it, because it is not that big of a deal long term. If it passes Toyota WS spec, it will be fine.
b) Wait 5,000 miles until next oil change, then just do the transmission again, this time replacing with the Genuine Toyota ATF WS. I guess that would kind of be like a 10,000 mile flush?
c) I am literally doing damage by the 100 miles, and should change the transmission fluid asap to Toyota WS.

FYI, the car has been generally well maintained throughout it's life on the PM schedule. I don't want to do something at 100,000 that seems fine now but will prevent 250,000 + unattainable because of transmission damage or wear.

Thanks again. - Matt

 

Thanks all for the advice. I essentially got the answer I was hoping for, which was I didn't make a mission critical mistake. I just wanted to not have any heartburn waiting another 5 to 10 K before going with the recommended approach and switching back to Toyota WS. When I drain the Castrol, I will update the thread on how it looks after 10-20 K in the transmission.

Yall are so much better than the Autozone people.
Have a nice weekend. -Matt