Flat and percentage behave very differently
A flat deductible is a stated amount: a thousand dollars is a thousand dollars. A percentage deductible is a share of the dwelling limit, so on a three hundred thousand dollar limit a one percent deductible is three thousand. The second rises automatically as the limit does, and nobody is told when it crosses what they could comfortably pay.
Some perils can carry their own deductible
Policies sometimes apply a separate, higher deductible to specific causes such as wind or hail. Holding a modest standard deductible alongside a much larger one for the most likely peril is a common and unpleasant surprise.
The right deductible is the one you can actually pay
Raising it lowers the premium, and the saving is only worthwhile if the figure remains payable on a bad day. The honest test is whether you could write that check this month without borrowing.