what 'less' mean in this sentence?
It's a bit boring, but quite important to me. Thanks for reading and answer.

What does 'less' in this setence? It's appeared twice, made me very confused.
What is the relation between 'submittals' and 'monies' ?

'Payment shall be made on approved invoices submittals less retention monies (if any) as
provided in Schedule of Rates hereafter, and less other amounts (if any) due to the Purchaser
by the Sub-Contractor'

Question

what 'less' mean in this sentence?
It's a bit boring, but quite important to me. Thanks for reading and answer.

What does 'less' in this setence? It's appeared twice, made me very confused. 
What is the relation between 'submittals' and 'monies' ?

'Payment shall be made on approved invoices submittals less retention monies (if any) as
provided in Schedule of Rates hereafter, and less other amounts (if any) due to the Purchaser
by the Sub-Contractor'

Answer

here less means "minus"

Answer

It refers to subtracting the retention monies and other amounts from the invoice totals.

Answer

Payment shall be made for:

(invoice amount) - (retention fees) - (other fees chargeable to purchaser)

"on approved invoices submittals" = if invoice is submitted and approved as valid

"retention monies" = "retention feels", or fees payed in advance to retain the service.

Answer

It is a very awkard way of saying money prevoiusly paid or deposits that were paid.

Answer

It might mean "to a lesser extent"