Horse Power vs. Fuel Economy?

In my outboard motor experience (fair amount of outboard experience and currently have an I/O - no experience with inboards YET), I have noticed that in some cases you can actually purchase a larger HP engine and achieve better mpg/gph depending on average RPM/speed/weight/etc. If you are pushing a smaller engine hard, it may be that a bigger engine may actually give you better fuel economy. I cannot stand to be under powered so as I begin my search for a real wake boat, was wondering what your experience is along these lines (i.e. pay for the power up-front and you will not notice a big difference in fuel economy or you may get better economy since it is used under load most of the time). Before you call me out, I assume some may make the statement that if you can afford a wake boat, you should not ask about fuel economy - I have money but am still cheap.

Thanks in advance for the feedback.