Just off the top of my head.....I'm assuming you're talking about storing this (for whatever period of time)????
If you're talking about mixing more of the two together than I'm going to use in a single tank, I wouldn't do it. I'd be afraid the two wouldn't mix well, together (sans water or label-directed dilutant) and I'd get a "hot" (or weak) mix.
Why would you want to do this? Just curious.