Good question! I would think that it would be the same, unless the high dose could cause some sort of instant blockage, as the same total amount must be metabolized. I do remember seeing somewhere from someone (don't know if it's creditable) that there was less metabolized by the liver the first go around with higher doses - but again unless sudden blockage was a concern or possibility I don't see how it would matter.
I personally would take 20mg AM and 20mg PM myself, but then again what else are you taking.... In general I would split.