Offer - Commission Compensation Terms ?

Offer - Commission Compensation  Terms ?

BLUF = Are these normal compensation commissions ?

Detail: 

I am a high tech traveling employee who services expensive electronic equipment 24x7x7.  These positions pay very well.  Salaries in the range of $85K to $ 130K are not uncommon.

I received an offer.  In addition to a good salary, there are also commissions paid for any new business that might follow me to this new company.

I've never been paid a commission and don't know if these compensation terms are typical.

To make the math easy, assume a service contract costs $100K

Here are the commission terms offered to me:

I get paid   1.25%   depending on how quickly the customers pays.

Days Past Due        % of commission paid

0- 60                                     100
61 - 89                                     75
90 - 119                                   50
120 -179                                 25
> 180                                         0

What do you think ?