TAI, UTC, and GPS and LORAN-C time are all the same time scale but at offsets resulting from having stopped adopting leap seconds at different points. The only confusing thing is that we tend to talk about TAI's variation from UTC rather than the variation of each system from TAI, which is fixed for everything but UTC (until 2035). We can thus sort of discuss them like time zones:
UTC: TAI-37s
GPS: TAI-19s
LORAN-C: TAI-10s
UTC will stop applying leap seconds but hasn't yet, so the offset for UTC could potentially change. Once UTC stops applying leap seconds, they will all be fixed and these offsets will just be technical details. Of course the whole thing has actually become obsolete in the case of LORAN-C which was shut down, but it seems less likely that TAI will fall out of use.
