When I purchased my Brolin Arms 1911 Government L45 it came with a flat housing and yes, I shot low. So I "upgraded" to an arched housing and loved it. Then I added a Chip McCormick High Ride Beavertail safety with "memory bump." After shooting my RIA 1911CS with the flat MSH and finding I shot well with it, I changed the MSH on the Brolin full-sized pistol back to the original flat MSH and found that it now made no difference. The high-ride beavertail and memory bump seem to have made the arched MSH redundant and unnecessary.