It's possible that Sumner recorded them in '95. I just always assumed that they were the unused '88 vocals.
Mainly due to the fact that the band were in 'can't be arsed' mode around '95 and probably thought 'why bother re-recording them, when we have unheard versions sitting in the vaults'.
With Let's Go, I think Baker / Sumner used the vocals recorded in 1987. From another thread:
Johnny James wrote:
Some details:
The original (and unreleased) version was fully recorded (with vocals) as part of the Low Life sessions late 84 in Britannia Row. In Jan 85 it was even part of an early draft for the album. By mid Jan however they replaced it with The Perfect Kiss (the band's first single on an album). There is a very rough recording of this in circulation.
Fast forward to the Salvation session (Pluto Studios), they totally re-recorded the track and do seem to have also recorded vocals for this as there is a rough mix in circulation. These vocals are a close match to the ones you hear on the 94 version.
The 94 version seems to have been reworked and re-produced using the Salvation multitracks, including the vocals recorded (but not used) from that session.
The Confusion thing was always puzzling to me. There's some of those mixes, still to this day, that I have trouble working out which vocal they've used. Some of them are easy to spot, but others not so much. I think some of them use Sumner's backing vocals from the '83 version high in the mix. Also, I've also suspected that one or two of them might use the '87 vocals, at least in part.