From what I understand & my talks with HP, there are 2 parameters.
1. EVDO Parameters - Required to latch / authenticate to EVDO signals. HDR Username & HDR Password are EVDO parameters.
2. Netconnect parameters - Required to start DATA (1x or EVDO). Earlier we used to login either by using MDN as username & password or by RWORLD username & password. These parameters are needed to access data & also billing is based on this.
Now, based on above facts, I conclude as below, (Pls correct me if I am going wrong)
a. Even if 1 is incorrect & 2 is correct 1x will work & evdo will not work.
b. If 1 is correct & 2 is incorrect 1x or evdo both will not work.
c. Suppose u r using mdn 93xxx with meid : ABC & activated evdo on this meid & using internet with username / password as net, then when u change the handset, evdo is still active on old rsn-mdn pair i.e 93xxx : ABC. So, if your handset buyer uses evdo on ur handset with rsn ABC & username n password as net, then u will be billed since meid ABC is linked to your no. 93xxx. So, whenever u change handset, immediately re-activate evdo on new meid so old meid-mdn pair would be cancelled n new meid-mdn pair would be active.
Hope my explanation & conclusion is right & helps the community...