My dentist wants to install 6 crowns all at the same time, is this typical?

It's very normal to do 6 crowns at once! Dentistry is like art work, the porcelain crowns are made with a special combination of porcelain powders.  When they are all made at the same time, they are all made with the same batch of porcelain, meaning they will all look the same shade.  Also, when they are all made together, they will all be made to match and flow together when it comes to their shape.  Additionally, they can be made to function properly! Hope this helps give you a visual!

This is not an issue. In fact it is better to do #22-27 at the same time so that the esthetics, anatomy, and color can be matched

I agree with both of the other dentists Doing 6 crowns one at a time has MANY more issues than doing all at once.  The results are more predictable when done at the same time, from esthetics to function. Doing then all at one is definitely the way to go 

My assumption is that your front teeth are worn down to necessitate crowning them. It would be typical to crown all of them at the same time since they should work in harmony with each other. To build them up together as a group makes sense. 73? No problem!

Doing 6 crowns one at a time has MANY more issues than doing all at once.  The results are more predictable when done at the same time, from esthetics to function.