found what i'm looking for

few questions about this before switch over from orange.
Pay Monthly - Viewing Bites is free the duration of your contract. Things like WAP chat and downloads costs extra.
is this the case with the £10 sim only too? browsing is free(football scores for example)?
2. Carry over: If your Bundle is renewed on, or changed to a different Bundle (any type, any size) by, its renewal date, any unused allowance in your existing Bundle will carry over to the next month (but not any month after that). If you do not renew or change to a different Bundle by its renewal date you will not be able to use any unused allowance.
does that means only the first month your unused allowance is carried over or does it simply mean there will only be a maximum of 600 minutes and 600 texts at any time. so say i don't use my phone for 3 months the maximum will be 600 texts etc instead of 900?
thanks for any help