...and they will still load the premium to cover your claim, so the most you'll save is whatever the percentage it is that they take off for a claim.
That's not really how it works.
They will load the full premium "because of your claim" not "to cover your claim"
As someone who has claimed, statistically you are now a higher risk (talk to an actuary for further details of how and why) and as premiums are calculated from actuarial risk tables, higher risk means a higher full premium.
Then once the full premium has been calculated, they will apply the NCD, if you had it protected. Of just charge the full premium if you didn't have it protected.
So although your insurance will rise after a claim. It will rise by a lot more if you didn't have your NCD protected.