Consistency from all 5 racks in commercial convection oven?

IMHO all I can say is that in my experiences with convection ovens (and at one place I had 12 of them all going at the same time) is that

the act of playing "musical" shelves with the pans is normal. The physical turning of the sheet pans and the uneven baking between the shelves is normal. There will be "hot spots" in the oven as well, even if it is calibrated perfectly.

What is being baked, how many are on each pan, all have a valid action upon the baking.

Perhaps someone else can give you a better idea.

Chefross is right

 You will find inconsistancy. In most cases,but  not even close to what you would find in normal oven.  Lets say your formula calls for 350 for 15 minutes. By putting 5 trays at a time in now you will have to increase by maybe as much as 10 minute because of the volume. All heat rises even if the air is disturbed so yes you will still have to watch and rotate.

         As far as a rotary oven they are expensive but are great.. In many cases the rotaries give more room height wise between shelves so you are not confined to cookies only.

Convections are a work horse, and you need a thoroughbred.

I've worked at many a place that had a dough sheeter, which ensured me a consistant thickness of dough, and teach rack bakes differently in a convection.

You can't fight the law,  and the law says:

-Heat always rises

-Squirrel-cage fans blow only in one direction.

That being said Rational oven fans blow in one direction for, I think 90 seconds, then reverse for another 90.

Best oven for baking cookies is a deck oven.  Separate top and bottom heat controls  Carousel ovens are pretty good for even heat too, but not as common as decks 

In my opinion the best oven I ever used for VOLUME anything was a Middleby Marshall Rotary oven, But then they go for about 25000. I find deck ovens good for pizza. Combis are great also but not for your purposes.