T5 F13 & F8 LED conversion double whammy

Greetings,
First post here. Would be most grateful for any expertise available on this issue. I am trying to convert 2L fixtures to LEDs. They each have (1) F13 T5 and (1) F8 T5 end on end. I ordered Type B (ballast bypass) LED replacements thinking I'd bypass the ballasts, install the tubes, and send an invoice.

BUT, got hit with a double whammy.

1. The tubes I received are significantly wider than the existing tubes. New LED tube is .74". technically T5 tube should be .625" diameter. That said, the old lamp, looks to be quite a bit smaller then the new lamp. New lamp won't fit in old fixture. Researched T5 tubes to try to find one smaller diameter and all that I could find are .74" diameter.

Has anyone run across this issue? The existing lamps are labeled Satco F13T5/CW A20. I can't find that lamp online, with the 'A20', but otherwise the Satco lamp is .625 diameter. Anyone know what the 'A20' is? Anyone know of an LED replacement with matching diameter?

2. The fixtures have rivets and no access points to where the ballast would be. Best I can tell, the existing fixtures don't have ballasts in them. As far as I know, T5 fluorescents can only operate with a ballast. We looked around to see if there could be a remote location housing the ballasts and could not locate them. Also noted that black and white wires run directly to the tombstones.. making me think these are already on line voltage.

Does anyone have thoughts on what the status is of these fixtures - are they on a ballast somewhere or is this a T5 fluorescent running on line voltage?

I'm thinking my only option may be to recommend removing the fixtures and installing LED strips or undercab type fixtures. Unless anyone has some light to shed on this scenario?

Many Thanks,
Bret

In the long run it is probably more cost effective to ditch them and replace with LED fittings.