To be honest I dont know, Im dubious, at least from an absorption point of view. But maybe splitting the dose/applications results in a more favourable pharmacodynamic profile.
The reason Im dubious about splitting the apps is that unless you are also increasing the daily amount by doing so, you are still only applying X-amount of compound: 10% of 50 is 5 whether you split that 50 up into twenty doses or just do the one.
Pat Arnold talks as if 10-20% is the absolute absorption ceiling, regardless of how lipophilic the compound is (and when we are restricted to our current carrier/solvent technologies). As he noted, the obviously crude way of improving absorption is to scrub the top layer of skin (stratum corneum) with a brillo pad, removing as much of the inpenetratable dead skin as possible and expose raw flesh and blood vessels.
But at that point you may as well pin.
Im not sure how literal to take him in regards to that 10-20% best-case-scenario, but like I said earlier, Ive yet to read any science which refutes his assertion.