gprs sms transmission speed ?

[address@hidden]

Does having a GPRS modem/phone speed up sms delivery or not ?

(
http://en.wikipedia.org/wiki/GPRS
"GPRS can be used as the bearer of SMS. If SMS over GPRS is used, an SMS transmission speed of about 30 SMS messages per minute may be achieved. This is much faster than using the ordinary SMS over GSM, whose SMS transmission speed is about 6 to 10 SMS messages per minute"

http://www.mobiledatanow.com/support/supported-sms-modems
"These modems will send/receive around 10 messages a minute."
( But both modems presented, TC65T and M1306B, are GPRS capable, why only 10 SMSs per minute ? )

I've seen other pages mentioning similar sms transmission speeds, way below what wikipedia's 30 sms per minute, or saying that GPRS does not speed up SMS transmission.
Or are there extra costs activating GPRS just to send SMS ?
)

Thank You