We all react differently.
I'm on Tamoxifen as well as other meds and I don't suffer hot flushes. I suffer joint and bone pain but that doesn't mean Tamoxifen is the culprit, it could be the other meds or a combination of both, who knows! What I do know is you need to find a happy medium, including time of day that you take it. You'll be fine - I suggest that you settle into one brand and don't swap from a generic to another as the body needs to adjust to the routine. Take care