Lower pitchers are called lowers because....

[marvin1997]

I never knew they would differ THAT muchThis is my viking x xkuchinggensis:





The one on the right is two weeks earlier than the big one...and I didn't use anny fert...I actually let them sit on another pot but after they drop down I just let them sit on the floor...And the big one was forming and...tadaa!Let every hanging nep of yours that has lower sit on the floor!!!

[caseyhoo]

It may be because the plant is new and stress. So, pitcher is small at beginning and it is settle down now. Just 2cents

[marvin1997]

Zduuno I thought it was the floor haha!

[NepNut]

Actually it's partly true... Pitcher developed resting on the ground is usually bigger and tends to be more squat (roundish) as well. For your case, this might be the result of resting on ground and plant started to acclimatise to your growing condition like Casey pointed out.

[delphiguy]

I have also noticed that pitchers that developed resting on something is more
bigger, may it be the potting mix or maybe another pot or maybe another
leaf... than the ones left hanging in the air. It could be because those
pitchers resting on something doesn't stress the leaf it is attached to.

[NepNut]

Yes, I also came to the same conclusion why the pitchers developed resting on something to support it's weight will tends to be bigger. I think it's a natural reaction from the plant if the pitcher is develop without somekind of support, it'll reduced it's weight by producing smaller pitcher.

Actually, it's not only lower pitcher, same thing happen with upper pitchers too... If the tendril can grab on to something, the upper pitchers develop that way will also tends to be bigger compared to the ones that the tendril is dangling freely (if develop at all)... this is what I observed personally.