Yeah but it'd need to ignore the scouter numbers. Does Masenko need to be > Kikoho?
Btw it's tricky anyways because if Piccolo thought the Kikoho would have killed Nappa, then he would have needed to be sensing Nappa's powers in off ways. Like, he can sense that Nappa is >> him but he can't sense the power Nappa was displaying there accurately? Why can he sense the Kikoho accurately though?
Maybe it goes back to Nappa not being able to power up in the traditional sense like the Z warriors. We assume that a scouter would read Nappa as his full power (~ 7,500) but that sensing chi is trickier. Like, Nappa isn't suppressing but at the same time, is masking his full power from natural chi sensors in a different way than warriors who can control their power would. Maybe similar to how chi sensors can have a more real feel when the opponent is fighting rather than just staying around.
It's like, Nappa was fighting but, by not using full effort, natural chi sensing can't feel his power so accurately as when Nappa/Vegeta really tries, flexing their muscles and using all the abilities, instead of fighting in a more casual level. But still, since Nappa isn't suppressing his chi in the same way the Z warriors could, it's possible that the power he is displaying effort wise, which why Piccolo and co. could sense, isn't totally proportional to Nappa's durability. If it's more of an effort thing rather than a real suppression as in, lowering his chi to that level in specific, it could be argued his durability could still reflect something closer to his full power instead of the level they can sense him at.