Papasmurf said:
Well he did tell Jheese that he himself had only just realized that he's surpassed Saiyan limits and getting close to the Super Saiyan, so it seems like whether he got stronger from the nap or not (don't believe that personally), he didn't realize how much power his zenkai gave him until then. Plus, he knows Goku can just amplify his power at will with Kaioken.
Well now that I'm reading the quotes again, in the original line Vegeta didn't exactly say "I've realized it
just now", he only said "the truth is that I've realized it too", so nothing of being some sort of realization only at that moment. Here's the quote:
Chapter: 289 (DBZ 95), P6.1-2
Context: after Jheese freaks out over Vegeta's new battle power
Vegeta: “That’s right…I’ve surpassed Saiyan limits, and my strength is still increasing more and more…The truth is that I’ve realized it too…That this extension of my power isn’t merely what you’d call giftedness…In other words…I’m steadily drawing near…to becoming a Super Saiyan!”
"I've surpassed Saiyan limits, and my strength is still increasing more and more..." - it really doesn't seem like he was referring to his past Zenkais, since besides having surpassed the Saiyan limits, he
is still growing strong, implying something that's still happening.
Also, look at this:
http://mangafox.me/manga/dragon_ball/v25/c096/13.html
Vegeta: "I'll deal with you at my leisure once Freeza is finished! By then, after all, I'll be a Super Saiyan!"
The "I'll be a SS" definitely implies he is banking on the idea of still becoming stronger, unless he expects to gain a massive auto evolution recovering from a near death experience in the middle of Freeza's fight.