Debi Check mandate requested at 5 times the premium value.

Tracker has requested a Debi check mandate for 5 x the premium on my bank account. While I understand how this works surely the mandate held cannot be at 5 times the amount and should be at 1.5 times. I have requested them to correct this and instead of reading the query , they send me an information sheet to explain how Debi check works. I don’t need an explanation as I’m fully aware of how it works. Please explain why your Mandate request is for 5 times the value of the premium. While you will never have a reason to utilize that mandate for that amount as I’ve never missed a premium nor will I,I am not comfortable letting you have a mandate for 5 times the premium. Please explain the rationale of this and point me to the PASA regulation that allows you to request a mandate for 5 times the amount.