If the website that you are referring to is rawmarks.info, then it is important to note that the marks available there are HSC exam marks, which are subject to alignment, not scaling. Alignment is a process that NESA performs that modifies raw marks according to band descriptors of a particular HSC subject, and it has no effect on your ATAR. The marks that NESA sends you on the day of HSC results release are aligned marks. On the other hand, scaling is a process that UAC performs when calculating students' ATARs, and students are not informed of their scaled marks.
To answer your question, the alignment of Ancient History seems to be the best compared to Ancient History and Modern History, although the difference is not substantial, not to mention that alignment has no effect on your ATAR anyway as mentioned. In terms of scaling, History Extension also appears to scale the best compared to Ancient History and Modern History. The fact that Modern History is said to scale relatively well is good if History Extension scales better than Modern History, because that would indicate that History Extension scales favourably (as opposed to saying it scales better than certain subjects, which does not necessarily mean that it scales well).
With that being said, you should focus on performing well across your subjects, regardless of their scaling. The better your performance, the lower the effect of scaling.
I hope this helps!
