PBS dependent visa extension fees with ILR main applicant

[ijd]

Hi, I have got my ILR with 5 year route (Tier 2 general) last week and got BRP that has expiry date 31-12-2024. I have my wife and children where they are not eligible now, since they will be completing 5 years on Apr,2024. So I need to extend their PBS dependent visa before 16/12/23.

I created the online application which asked my BRP (gave my ILR BRP) and CoS duration ( gave greater than 3 years since my last CoS was 5 year route).

On submitting the IHS it asked for work end date and I gave the ILR end date (31-12-2024). So it calculated for 1 year - I believe this is correct?

on submitting the application it is asking to pay 3000 for 2 applicant. I believe only greater that 3 years application fee is £1500.

1. Why it is asking me to pay for >3 year fee, is that because I gave my CoS as greater than 3 years?
2. If yes I don't need greater than 3 years extension. Only need less than 3 yr extension. How do I mention this in the application?
3. I have already paid IHS, so I cannot restart the application correct?
4. Will there be any issue since I have Paid only for 1 year IHS and application is made for more years?
5. How can I get the excess fee I paid for the application?

Thanks