Calculating net impact on receivables for giving discounts

Can someone please help me to understand?
While calculating net impact on receivables, shouldn’t we include the percentage of receivables who didn’t opt of discount?
For eg. Wallace co. is considering offering an early discount of 1% for payment in 30 days. It expected 35% of the customers would opt of discount and will pay in 30 days. Receivables are $4,500,000 and average customers takes 60 days to pay, assuming a 360-day a year.

So, reduction in receivables would be $4,500,000 x 30/360 x 35% = $131,250 but this is only for 35% for another 65% who didn’t opt for discount needs to be considered for overdraft , isn’t it?