Recently recontract at Sitex and received my first bill with shocking amount. Charges was still under old plan plus additional new plan charges. If you go paperless billing , please recheck your bill monthly coz u never know what Starhub is charging.
First bill cycle tends to be higher than normal due to the various charges involved. To clear your confusion, do take a look at this post https://community.starhub.com/t5/General/StarHub-How-To-s-Understanding-Bill-Pro-ration/ta-p/144224.
Hope this helps.