I, too, ran into this flaw...
I multiplied 1kohm*5microF, and was surprised to find:
1. I must use mF rather than Greek microF for the capacitance. I am a novice, though, so I may have missed something.
2. The result expanded units to something ugly using [[kOmega]]. I am surprised that at this late hour in Maple development that we still see [] for units AND units are not automatically simplified in the unit base that we are using.
3. The examples above are clear enough, but still amount to r-clicking and selecting Units>Simplify. Typing the command doesn't remove the burden of simplifying.
4. Maple correctly suggested units of seconds for my example, so it apparently knew what to do. So where is the global option to automatically simplify units, and why are we still using [], and why are microFarads mF, even in light of ASCII-based history?
I looked in Help and did a web search for answers, but came up empty...