NDAX discrepancies in transaction reports

Has anyone else encountered this?

I'm going to use hypothetical numbers:

I transfer $1,000 into NDAX, and make a purchase of a coin.

My CAD account balance then reduces to $500.

My NDAX report shows that I paid a total of e.g. $502. That is, it is saying that I paid more than what my actual CAD account balance reflects. This $502 is the correct calculation of [(number of coins bought x price per coin) minus the fee in coins] x the price per coin in CAD.

However, although the above calculation is done correctly, it does not reflect the cost of the transaction shown in my actual account balance in CAD ($1,000 - $500 = $500).

Let me know if this is unclear. I'm avoiding the actual transaction numbers.

Thank you!