I have a query regarding KVS if a regular user would be so kind....

I need to book a flight from LHR to SEA at some point during mid Sept, staying for around 16 days or so.
The dates are in no way fixed so I can work around a good flight price.

Ideally I'd like to buy a WT+ seat and upgrade to J using my Avios, but BA's site is currently showing no upgrade availability to SEA on any day.

Can KVS give me the information I need to make a booking at the best price possible given the date parameters?
I have no issue in paying for the software, but there's not much point if it can't do what I need.

Thanks in advance.