It really depends on a number of factors. You are right that the majority (
but not all) of the conversion to 11-hydroxy-THC takes place in the liver, however, sublingual absorption is much more efficient (and quicker). It's really a question of this; Does the increase in 11-hydroxy-THC production outweigh the decrease in absorption?
The answer to that also depends on a number of factors including your diet (down to what you have eaten in the past few hours), your body mass index, the type of edible you consume, etc.
Another aspect to this is that while the majority of the more potent 11-hydroxy-THC production takes place in the liver, so does the production of the
non-psychoactive 11-nor-9-carboxy-THC.
In my personal experience Tinctures are more potent when held under the tongue (taken "sublingually")