complicated upgrade/booking class question
 

I am going to be booking SJO-IAH-EZE-IAH-DTW-IAH-SJO soon for sometime in May

I want (or want to have the option to) upgrade the IAH-EZE-IAH segments to BF without paying gazillions

it turns out that if I price SJO-EZE-SJO in H the price only goes up for about 300 dollars (as opposed to the 800 or more in copays)

I am wondering if my upgrade plan would work if I go to a ticket office and get the IAH-EZE segments in H and leave everything else in the cheapest option?

does it work like this? or is there some sort of fine print somewhere that says "the entire itinerary must be booked in H in order for the copay to be 100 / leg" ?

I am fairly certain that the fare buckets of the only the BF segments drive the copays.

Last year I had a multistop itinerary that included CO and NW flights, some in BF and some in regular F (all upgrades). The outbound BF segment was originally H, the inbound one was S. There was no copay on the H (now would be $100) and $450 on the S (now would be $500). I think one of the CO flights was M/N and the NW segment was B.

Bottom line: you shouldn't have a problem.

The only minor potential problem I can see is that you might end up having to price IAH-EZE-IAH as an H fare rather than SJO-EZE-SJO as an H fare and it might be more expensive that way. Certainly worth asking/trying, but don't be surprised if it doesn't work out the way you hope.

thanks for your answers Tommy and sbm.....

Sbm...that output is from the kvs tool , correct?

Yup.