I am continually befuddled by AFI's NTA reports and how closely...

I am continually befuddled by AFI's NTA reports and how closely AFI's performance aligns with that of the index and an index ETF - In this case, I've used VAS as an example. Disclaimer, I don't hold VAS in my portfolio. AFIC state their returns as of *period ending March 2024;

As a total simpleton, can somebody please clarify and/or explain the massive difference in what AFIC report as opposed to price charts of that of the XJO, VAS & AFI. Yes, I get the reference to the inclusion of franking for those can take "full advantage of franking credits". AFIC claim that over a 12 month period (ending 31st March 2024) that their 1 year return has been 17.8%. Is this all in the *wording - ie; "Net asset per share growth" vs. actual share price performance. Anyone?

Here is the 12 month price chart of AFI (in blue) v XJO v VAS;


Here is the 3 year returns;



Five year returns;



Ten year returns;



AFIC Average Annual Total Return;