My cat, Bob, had low potassium for a long time. In him, it didn't cause twitches, however. Just overall muscle weakness, mostly in his hind legs.
To emphasize what BJ said about getting bloodwork done...
When Bob was diagnosed, his blood panel showed normal potassium levels. Less than a month later, he was below normal, and he stayed that way for about 3 months before he tested again in the normal range. I had to administer sub-q fluids during that time that had potassium added to them in order to bring his levels up.
So even if Seymore tested normal at diagnosis, a new blood panel would be a great idea. It might show other numbers that are above or below normal which could be the cause of the twitches (besides potassium).
Carl