Definitely not...Caltex Vortex 98 is a separate product from both BP and United/Peak...it is made by Caltex themselves. There have been reports of the odd bad batch of Caltex 98.

There is no drama swapping between different 98 brands (assuming they are all actually 98) if your car has a re-flash tune. If you are running an aftermarket ECU (eg Autronic, MoTeC) it may be worth checking the tune between brands just in case...