import re
strings = ['ABC WS YMQ234.03WS TOY234.03USD468.06END','FUR BB LAB Q10.00 199.00USD209.00END','YAS DG TYY Q AWSMSN11.32 2503.08LD VET Q JKLOLE11.32 2503.08USD5028.80END','PPP VP LAP Q10.00 M342.41EE SFD Q10.00 282.24USD644.65END']
rx = r'(\bQ\s?[A-Z]*)?(?<!\d)(\d+\.\d{2})(?=.*\d\.\d{2}END)'
for s in strings:
    matches = [x.group(2) for x in re.finditer(rx, s) if not x.group(1)] # note the if condition that drops unwlecome matches
    print(s, matches, sep=" => ")