Kittens crying while using litterbox

So I am having fantastic success with Ara's kittens using the litterbox- after just a handful of accidents all 5 are consistently using it in less than a week! I have never had a litter take to the box so fast. 

However, whenever they "assume the position" they cry. Not just a meow but a cry. And, they cry when they are both peeing and pooping. They are all passing a normal amount of urine, and their stools are solid and a good color (ugh I hate my life that I know what a good color is). Is this just a behavioral thing they are picking up from each other? Do they truly want to get everyone's attention and have an audience while going? Or, does it sound medical? If it was just one doing it I would be really concerned, but since they all are it makes me think it's just some strange kitten antic. They are in general a very vocal litter so it's not like it's stone quiet with intermittent cries- they are all pretty much chattering away 24/7. 

Has anyone else seen this before? 

The kitten I just lost would cry when he pooped, but not when he peed. (He had a heart defect). I think he did it to draw attention to his self. Not from me so much, but from my other cat.

Most of my kittens like to announce they are using the tray, it's a chatty meow though not a cry.

When I adopted Naku (who is a chatter box) I was worried about his crying pre, during, and post litter time. During his initial vet visit later in the week, he checked out fine. Vet said it was just a testosterone thing (because he was just fixed in the past month then). He still does it and at this point, I think he just likes attention and likes to talk.

Thanks all. I really do think it's an attention thing. Earlier today I peeked in on them and one woke up and went to the box while the litter mates were sleeping and didn't make a sound. Also, my brother was over playing with them and the two who used the box during that time were very deliberate in looking right at him and crying. I'll call the shelter vet tomorrow just to be sure, but I think they are a bunch of attention-seeking divas!

It is a little weird though.

Yes, it seems clear it is attention seeking, but arent cats supposed to try to do this discreetly, as they are rather vulnerable in such moments?

Although I suppose it is a sign they feel safe and comfortable in this home, as they do dare to overrule the safety precautions.