Why did Piccolo make the boys fuse as SSJs?

[AvatarReiko]

Why did they make them go SSJ before fusing instead of simply getting Gotenks to power up? Why did he just assume that boys couldn't go SSJ after fusing? Both Goten and Trunks can go SSJ individually, so logically Gotenks would also have that ability.

[KBABZ]

Why did they make them go SSJ before fusing instead of simply getting Gotenks to power up? Why did he just assume that boys couldn't go SSJ after fusing? Both Goten and Trunks can go SSJ individually, so logically Gotenks would also have that ability.

The mechanics are explained at some point, here's what I recall. Basically, Fusing using the Fusion Dance exponentially multiplies the battle power of the fusees. Them going Super Saiyan would therefore multiplier their Super Saiyan battle power; note how Gotenks shows up in his base form despite Gotenks and Trunks being Super Saiyan when performing the dance.

Where it gets confusing is later on where this rule is treated quite differently. In the Room of Spirit and Time, Piccolo is surprised when the boys don't turn Super Saiyan and then are able to do it as Gotenks, implying that it was actually more about Gotenks possibly not knowing how to do it, which is weird and confusing in light of how it worked earlier.

[Lightdasher]

Where it gets confusing is later on where this rule is treated quite differently. In the Room of Spirit and Time, Piccolo is surprised when the boys don't turn Super Saiyan and then are able to do it as Gotenks, implying that it was actually more about Gotenks possibly not knowing how to do it, which is weird and confusing in light of how it worked earlier.

I always figured this was because Gotenks wanted to save Super Saiyan for later on in the fight. He seemed intent on showing off as the conflict progressed, which is also weird since we all knew he had a time limit.

[KBABZ]

Where it gets confusing is later on where this rule is treated quite differently. In the Room of Spirit and Time, Piccolo is surprised when the boys don't turn Super Saiyan and then are able to do it as Gotenks, implying that it was actually more about Gotenks possibly not knowing how to do it, which is weird and confusing in light of how it worked earlier.

I always figured this was because Gotenks wanted to save Super Saiyan for later on in the fight. He seemed intent on showing off as the conflict progressed, which is also weird since we all knew he had a time limit.

That's true too, although to my understanding he was saving Super Saiyan 3 in particular as a surprise. Bites him in the buttocks, of course! Him showing off and being cocky is precisely his primary character flaw.