Volt data massed up on export

I was asked to change the menu names of dozens of fonts. All of them are TTF shipped from MS Volt (few years ago) after correct positioning of mark to base. All I have are the TTF files, no vtp files…
So I opened the TTF in Glyphs and all I did was to change the font info, and export.
The precise adjustment from volt was gone!!!
Is there any setting in Glyphs (like in FLS5) to read and export the volt info intact?

OTF is not a saving format, but a compiled binary. It is impossible to reverse engineer everything, especially to reverse engineer stuff that was done with VOLT into AFRKO feature code.

If you just want to change the names and leave the binaries untouched, why not use ttx?