?
Why should it indicate the soap is laking? Either soap for that matter? To achieve the same only different I could easily just use more soap of either kind. The addition of two different soaps can sometimes give a result that neither soap is able to provide. My main soap is scent free but I do like a small amount of menthol which the "dob" of Proraso gives without the chemical fire I normally get with the green.
I could just as easily add Eucalyptus EO and menthol to the same unscented soap recipe when I make it but why would I when this 500ml tube cost me $6 and will last me a very long time.
Perhaps for your own benefit, if you haven't already, try a small amount of cream in your scuttle, load your brush with your favourite soap as normal and see the results for yourself. You may or may not like the results.
I hesitated to post that. I hope it didn't come across as smug, or arrogant. It's an honest question, the answer to which I was curious. I just assumed you were improving your lather, but if what you are really doing is not improving so much as making it different, cool, that's the answer I was looking for.
Shave on!