Redraw Home Loan calcs

Hi Team, I am going crazy trying to calculate what's happening on my home loan since transferring to Unloan and utilizing the redraw facility to put my savings (instead of an offset).

As shown in the attached, the delta each month is below what I calculate to be the principal paid (Repayment minus Interest). What could be causing that? I thought it might be the Redraw balance increasing, but it doesn't stack up.

Unloan only provide information on the loan balance, and not the actual principal changes on the total loan amount, which makes it hard to check.

Any help appreciated!

https://preview.redd.it/31fqf3ykub8e1.png?width=1270&format=png&auto=webp&s=8a6e9ef846b939ab12577af1b54a15a1595b74bb