So... I'm starting to grow a little bit tired of explaining Kaito V3's vocal range versus V1 range.
In a nutshell, V1 vocals had small ranges, your talking pretty much Gachapoid size here when I say that. Not only that but the phonetic system was still a little more basic, you see a rewrite happen along with VY1 and how databases are organized and run. Heck modern Engloids have phonetics recorded they haven't used since the V1 era according to the Gumi makers...
The V1 engine itself was crap... It was highly digital and clarity was lost quite easily. Yet these two reasons alone were enough to give V1 vocaloids flexibility that V2 vocaloids often lacked. And V3 vocals seem to wish for at times. And as vocal types are often a factor also in how well a vocal works with the engine, for some vocaloids the engine version played more in favor for then other. Miku versus Prima? Prima lost that one.
So yeah... People often say "Kaito V3 has a smaller range then his V1 vocal" without realising these factors at play. Kaito V3 has more samples per his voicebanks database library plug-in, producing alone highly quality results. His samples are in the same vocal range as his V1 era, but now there is no 'give' because of how much sharper the new V3 engine is compared to V1 in rendering voices and maintain clarity... Along with less digital noise causing his voice to sound more natural then before... Which leds to problems in itself...
In short, Kaito V3 has less overall 'give' because he sounds BETTER, you hear faults easier.
But hey, I'm getting a headache having to explaining whats gone on between V1 -> V3. I'm not expecting people to automatically know this stuff, but I'm beginning to wonder how much people care to wonder about this software at times and how it works.
I also fear what would happen if there was ever a update for the other V1 vocals Leon, Lola and Miriam and the expectations of fans. :-/