What did Trunks mean by "regular fusion" in the ROSAT?

[Hector]

"We've powered up enough to be equal to (Super) Buu in our regular fusion. So we'll let the fight drag on, then in the last five minutes, we'll do that Super Super Saiyan thing (SSJ3) and win."

By regular fusion, was he referring to Base Gotenks or SSJ Gotenks? I've always thought SSJ Gotenks makes more sense. I mean, if he thought they were equal to Buu in their base form, then SSJ Gotenks would be overkill, making going from base to SSJ3 pointless. If that's how strong Trunks thought they'd become, he'd have worded that statement differently. He'd have said something like:

"We're so strong we can crush him as Super Saiyans, but let's do that Super Super Saiyan thing just for fun."

 

[GreatSaiyaman123]

Base. That’s a Saiyan’s regular form. It lines up with Piccolo’s statement. The boys want to go overkill for show, you can’t argue about pointlessness here.

Of course, they were wrong, but that’s what the chapter presented.