Keep in mind that many parallel dual generator systems were not designed to run in parallel as a continuous combined load system, instead they were designed to provide continuous power to some application, so that they may be shut down individually for maintenance without having an interruption to the power output.
So typical operation may go something like this
Generator A is started and runs providing power
24 hours later Generator B is started, momentarily synchronized with Generator A
then generator A is taken offline and shut down for daily maintenance, oil check, etc.
24 hours later repeat with A taking the place of B.
I suspect this style of operation would be found on most MEP-701a installations when you consider the alternative that would often make more sense would be to provide power by a single MEP-002a at 5kw rather than a pair of MEP-701a's at a theoretical combined output of 6kw, especially when you consider the relatively better fuel economy per KW of the MEP-002a at full load (the 3600 rpm 1 cylinder MEP-701a is rated at .5 gph at 3kw full load, whereas the 1800 rpm 2 cylinder MEP-002a is rated somewhere around .6 gph at 5kw full load)