Not exactly sure if I understand you (my spanish is bad and g-translate wasnt much help) but just because you have 8 frequencies selected doesnt mean you will see an AP for each frequency. The AP list will only show what is available in that direction IF the AP meets the requirements of the SM (20mhz/40mhz channels, correct scann frequencieson both channel widths). So 4.5km away from a tower, you may see two or three APs.
Network entry threshold is used to eliminate APs from even being tried if the RSSI is too low and the SNR limits are used to prevent registration if the signal clairity is poor. If you are doing an area scan, set these to -100 and -5 snr and select your channel widths but no specific frequencies and you will see everything (eventually) that the SM can see.
Good operating thresholds are -76 and 10, this ensures that the SM has enough signal and clairity to provide continuous service without re-registering (service drops), but you will need to determine what is acceptable for your own network as a policy.