Clarification on Gamepass Ultimate conversion?

I've seen so many different things about this said and there doesn't seem to be a clear answer anywhere.

Last year I had a year of Xbox Live Gold. I converted it to a year of Gamespass Ultimate by using the "1 month of Xbox Gamepass for console for £1" offer from that time. About a month later, I used the "1 month of Xbox Gamepass Ultimate for £1" offer to
get another month. I have not purchased any time of Gamepass Ultimate other than those.

My subscription has ran out and I'd like to get some more time for gamepass. I've not had a month of gamepass for PC before, so I have the offer of that for £1. The FAQ for that says if you have XBL
or gamepass for console it'll convert it to ultimate, so would buying that 1 month of gamepass for PC for £1 convert any Xbox Live Gold time to Ultimate at a 1:1 ratio?

It also is very unclear on the gamepass FAQ about when a conversion takes place at the lowered rations, It only shows the conversion rates that apply "After you join Xbox Game Pass Ultimate" and doesn't say what they are when you have had a subscription
in the past, but don't currently have any. As I don't currently have a subscription to ultimate...what would the conversion ratio be for me? The terms for it say converted "to Xbox Game Pass Ultimate at a conversion ratio each based on days remaining"
but I have 0 days remaining, so what is it?

:)