Plumbing question

[oilfieldsafety]

So I was plumbing up my new (used) 90 and a question came to mind, this is my first system that will have a sump so I was more or less going to match what I have seen done on other systems that I have seen. Most of these have been plumbed with 1" line running from the pump to the tank even though the output of the pump was 1/2 or 3/4 inch. Now I assume that this was done with friction in mind and wanting to get max flow, but by going to a larger diameter pipe won't you increase your head pressure due to weight of the water column and in fact decrease your flow? Thoughts?

Shane