There are over 11,000 legal taxis haunting the streets of TP HCM, plus thousands of illegal pirates whose sole intent is to rip you off.
It is impossible to adjust all the meters in a single day, city inspectors are the only people allowed to seal meters.
During this change-over period you might use taxi's from the same company over the same route and be charged different rates, ONLY PAY THE AMOUNT ON THE METER,
I you have a real dispute ask the driver to call the police. (don't do what one Australian did, punch the driver and end up killing him)
If the driver tries to ask for more money, as often happens, say No! and invite him to call the police. THE METER RULES.
Always insist on your full change (it's the law), and if he doesn't have the right change - the drivers loose (they usually run two purses - one in the shirt pocket and the other in the trouser pockets.
Pay the tip after you have the change, they will learn.
Notes:
= Always make a note of the decal number and the plate number;
= Always make a note of the drivers name (from the IC card displayed);
= Always make sure the driver gets out, engine off, if you have baggage.
Pirate taxi's usually use magnetic signs (like fridge stickers) and unsealed meters. AVOID!