Yes, your right. But that 6/4 would not be considered a compound T.S.. It would be a simple one. There is always a confusion between T.S.'s when the top number is divisiable by 3. It can be both simple and compound. Some twentieth century composers make the difference by writting the note that gets a beat in place of the denominator, and the actual number of beats on top (numerator). So 6/4 as a compound would be a 2 above a dotted half note. The simple T.S. of 6/4 would written as 6/4. I'm sure with your experience you have seen both.