Net 30

Hello all,

I have a question about receipts & net 30. I have clients (apartment complexes) that I do work for as a contractor. I send invoices to clients at the end of each month. I also purchase material for repairs in each month & add cost (plus markup for material purchase) & have net 30 accounts with the suppliers I purchase the materials from. I get a receipt when I purchase material right then I also get statements from suppliers at the end of each month showing what was purchased in that month. I would like to enter receipt in QB as an expense (job supplies) and mark receipt as billable expense so when I create invoice it asks "would I like to add these billable expenses (receipts) to invoice." I am also wanting to add the net 30 bill from suppliers into QB as well so I can pay suppliers in 30 days after receiving statement/invoice from suppliers. My question is would this be "double dipping" or show up as expense twice sense I am putting it in as receipt each time I get receipt to be able to add material cost to invoice (to client) as billable expense (get reimbursed. Plus markup)? Or will it not show up as expense when I put the suppliers statement in as bill to pay later for material purchased throughout month?

Any help would be greatly appreciated.