The dosage was the same. I bought Pencor 2 mg and split the tablets in half for the 1 mg starter dosage. The tablets actually have the same shape for all the manufacturers. The 1 mg is circular. The 2 mg is oblong, the 4 mg is square. So you have an additional cue about what the dosage is.
While it could be some variability in the manufacturing process, it's also possible there were other factors involved. Foods I ate that day, sleep, etc. Still the problems disappeared when I went back on the Cardoxa. Strange.
Thanks again for all your advice, Sheryl.