Estimation of vs estimation on

Hi,

I am doing an assignment of Accounting from Uni.

I just need a simple(?) advice on whether I should use 'of' or 'on'.

From the following sentence,

Historically, the cash collection of sales has been as follows.

I just want to modify it like

The company's estimation of the cash collection of sales. OR

The company's estimation on the cash collection of sales.

...

But here I am not quite sure the difference between estimation of or estimation on...

I guess, when you use 'on' , it normally means something influences other things.

So in this case, a way of estimation that influences cash collection of sales.

Am I in the right track?

If I use 'of', just like above sentence, it is just the conversion of

The company is estimating the cash collection of sales...into noun phrase.

Am I right?

Thank you.