Yeah, the green one is their heaviest oil, to stand up to all kinds of wet and salty conditions. The
gold bottle is the super smooth one, with teflon and nano particle what-not, it's not the same. If you ever get a bottle of their stuff again, go for the gold bottle
It's not a big deal though.
I think the original Singer oil must have been something like SAE 15, maybe 10. I have bought very basic generic SAE oil 10 and it was lighter than Singers. The old oil wasn't completly clear and transparent, it had more of a amber color. I think what they sell these days is completely clear and colorless, at least some, I suspect a bit lighter. It's hard to compare basic mineral oil with their synthetic versions, since the syntetic types tend to be a bit gel like in their viscosity. Some heavy duty chain oils for bikes would be horror in a sewing machine, the very basic ones are often spot on the origial Singer oil. I just go on and on here, but I go for the light synthetic versions with teflon.