You can read about my thread here.
https://www.hairlosstalk.com/interact/threads/what-norwood-contemplating-taking-propecia.108556/
There's anecdotal evidence that switching to generics(from brand name, or even brands) causes shed. I haven't noticed a shed 2 months using a different generic. You can be safe and get the real thing but it's much more expensive. Generics work. I get mine from Costco also. Camber Pharmaceuticals was the first generic they gave me for first 6 months. Second generic was Ascend Laboratories and have been using for 2 months. I take 1 mg per day. Hair is maintained and still improving.
I felt stronger sides using Camber Pharmaceuticals and can tell it strengthened my miniaturized hair within 2 months. I felt less sides with Ascend Laboratories, which got me thinking it may not be working as well as Camber, but sides usually go away after a while, so take that with a grain of salt. Just take it, don't think about it(placebo) and monitor your hair every couple of months.
I noticed you were receding in a 2a pattern earlier in the thread(seems most asian recede this way), good you were able to get diagnosed properly. Asians also seem to respond well to finasteride.