Ann: Half Year Report and Accounts, page-23

sorry for the explanation that led nowhere thanks for clarifying the share loan structure.
so i guess the timing of the GM departing contributed to around $100k / HY (max) to the employment costs..
the other possibility i had thought was the hitting of certain triggers/overrides which contributed to one-off bonuses and incentives for certain dentists/management or perhaps earn-outs for prior acquisitions (usually not in wage line though).

failing the above, certainly as travelightor suggested, replacing retiring dentists with graduates is a possibility and would hurt the top and bottom lines in future.
however, given most of ONT's practices are in regional / suburban areas (also affordable rather than quality), the impact would be muted compared to an inner CBD practice and premium quality practices.

i suppose the only way we would know the truth is actually talking to management.