This pretty much explains it:
//
// Table for FREQ2 settings. (Vantage VUE - US 900 mHz)
//
static const uint8_t __attribute__ ((progmem)) FREQ_2[51] =
{
0x23, 0x22, 0x23, 0x23, 0x23, 0x22, 0x23, 0x23, 0x22, 0x23,
0x23, 0x22, 0x23, 0x23, 0x23, 0x22, 0x23, 0x23, 0x22, 0x23,
0x23, 0x22, 0x23, 0x23, 0x22, 0x23, 0x22, 0x23, 0x23, 0x23,
0x22, 0x23, 0x23, 0x23, 0x22, 0x23, 0x23, 0x23, 0x22, 0x23,
0x23, 0x22, 0x23, 0x23, 0x22, 0x23, 0x22, 0x23, 0x22, 0x23,
0x23
};
I don't know anything about the 466 mHz version.