You're right, accuracy would make a difference in the calculations, but go figure that almost every build focuses on trying to max hit rate unless you're gimp and stupid.
You should never be below 85% hit rate in merits. So just multiply the expected swings to account for your misses, which should fully be nullified since at least mnk's and thf's should have at least 10~20% extra attack rounds from KA, DA, and TA. So you can basically assume 100% accuracy worth of swings (0.85*1.2=~1).
This go back to the expectation that it will take you about 8.5 rounds to WS.
The most critical error (but one that is understandable) is somehow thinking percent change in the nominal number of hits (integers) is the same as the actual percent change in WS frequency, which is a consequence of non-100% hit rate. When it comes to dual wield/H2H, the "real" change in WS frequency can differ from the "nominal" by quite a bit.
Blah blah blah actual results may vary. No fucking kidding. Thanks for contributing nothing but the obvious.
If I go from needing 9 attack rounds to only needing 9 attack rounds 50% of the time, that's roughly a 5% increase in frequency. If anything I low balled the expected change by halving an extra time.
Regardless dropping a hit can create a noticeable (2%+) difference in WS frequency and produce a pretty decent increase in your total damage before considering the rest of the stats on Rajas or whatever stp item, or at least enough that Rajas will break even or surpass L/K always.
Of course no where along the lines that they would for a two-handed job.