The deed is done and the CC has been swiped so all WILL be well.
MEL>BOS>LGA, PHL>BHX>CDG>SIN>MEL
MEL>BOS>LGA with UA, PHL>BHX by US Airways, BHX>CDG by LUF and CDG>FRA by LUF then FRA>SIN>MEL by SG
Total is 25,485 miles and ticket cost, inc taxes = $3,549
Apparently ther is a US$500...