Yes - Taylor hit a MOST important aspect of testing.
I add a bit of oil to my winter windshield washer fluid, (alcohol and water for the most part) to add viscosity to reduce the evapouration rate. I use neetsfoot oil. The oil can be used by itself, but so far, I feel the WWWF + the neetsfoot oil, in my .32 and .40, gives better accuracy over a wider range of powder charges. One of these day,s perhaps I'll get a concrete test on that premise. I shake the WWWF + oil, then apply it to the pre-cut patches, which I carry in tins. (sucrets, candy, track's snuff or flint and steel containers, etc.) Done this way, there is virtually no separation, it seems. In a container, the loose solution will separate, but in the cloth, it doesn't happen.
Straight oil, ie: with Hoppe's Plus, Neetsfoot Oil, Lehigh Valley Lube, I've found in both my .45 and .40, require at least another 10gr. of powder over what the water based lubes will shoot.
For me, Olive oil has proven to be a poor lube additive - in the ML and in a bullet lube in the BP ctg. rifles. Innacuracy and fouling are it's main problems.(which is too bad as my wife buys it by the litre - ie: free to me)