Actually, you only need an atar or just above 98 to boost your ATAR to 99.95 under the 5 bonus points scheme. Yes I am aware it's added to the aggregate which you can even check here. https://www.satac.edu.au/documents/2016_sace-ntcet_uni_agg_atar_conversion_table.pdf
Thanks for the good info. Whereas SATAC equates 90 aggregate to 99.95 I used 95.5 aggregate based on a UAC table, thus the aggregate gaps from 99.95 down to 99.0 or 98.0 are much larger than 5 points.