>>211794002
This 'fair use' clause makes it look like it's to the discretion of the particular carrier you're with.
Also many mobile contracts give you the greater bulk of gb/minutes as part of a 'bonus program' that doesn't apply to roaming because it's a domestic offer, giving you the impression of overcharging when you're roaming.
That's why I've no difficulty believing bulgargreek gets 'overcharged' outside bulgaria