It is 2 years into a 3 times a year trip from South Florida to Singapore.
My home airport is PBI but I also fly out of FLL and MIA. All three of these airports enable me to connect to larger hubs such as JFK, NYC, Chicago, LAX and SFO.

I have flown on SIA, United, Lufthansa and Delta. I have frequent flier miles on SIA, United and Lufthansa.

I fly coach as per my contract for assignment. The highest paid was Lufthansa at $1800+ and the lowest with United $1145. Booking my round trip is not a problem. The problem comes in when I go to change my return portion.

I never know till I get to Singapore how long my stay is going to be. Usually it is 60 days but alot of times it is extended to 90 days.

This is where I need some advise as to booking.

United cost me the change fee plus they always tell me the class category I flew out on is no longer available and I have to pay for the next class. The last time this happened I found myself paying over $600+ to change my ticket. In other words 50% of the RT.

Singapore Airlines. The round trip price is usually about $150 more than the lowest. On the upside when I have to change my ticket it is easier to do so. Usually it is $20 but I am silver Kris Flyer so they wave that. Most times my dates are flexible enough to be able to fly outbound on the same ticket class and thus avoid higher class fee. Unfortunately the last trip was this summer at the height of travel season. My connection was through Frankfurt. THAT FACT COST ME $260. Still less than what a change usually costs through United.

Lufthansa costs $200 to $250 to look at changing your ticket let along any class upcharge.

With a high probability of extending my stay on the next trip I need some options. Should I try a hack ticket and buy two tickets, one each way? From what I can see this would add about $300 to most fares.

I have not booked my next trip yet but the dates are August 12th with a return on November 11th. Most likely I will need to move the return to December as I am planning some side trips.

My route of choice is usually pbi-jfk-frk-sin. Jetblue/Singapore but I have done the West Coast connections, IAH and Chicago as well.

Any pointers and or advise that I might be missing?