Three versions of the Australian MA15+ age rating

This is my first post, hopefully I put it in the right topic.

The certificate information area on IMDB appears with three different versions of the MA15+ age rating. One is Australia:MA15+, another is Australia:MA and the last one is Australia:MA-15. Out of the three, MA15+ is the correct format (source: https://www.classification.gov.au/classification-ratings/what-are-ratings) while the other two are incorrect formats of the age rating. Just in case people ask this, MA and MA-15 have never been listed as a format for the age rating on any platform or by the rating board, they have used MA15+ as the name of the rating since it was introduced in 1993.

It would be way clearer if the two other formats were merged into Australia:MA15+ (if that is even possible).