Wizfi360-con Low Power -10dBm

I need to solve our problem with wizfi360-con modules by phone, send me the contact and the time when and where we can call.
Due to customer complaints about the short wifi range, we did performance measurements.
We measured several WizFi360 modules that we had in stock. There were new pieces and used ones.
The measurement was performed on an Anritsu SpektrumMaster MS2711E device, which was directly connected to the WizFi360-con modules antenna output.
The measured signal level was -10 dBm, with some pieces even -14 dBm in the set Wifi channel.
But in WizFi360 datasheet is defined power of 12 and 19 dBm.

Is there something in the configurations of WiyFi360-con that causes such low performance?

please let me add that solving the isue of output power (signal level) is very urgent!!!
Currently approximately 1800 pieces of equipment with WizFi360-con are sold. Complains about signal strength and wi-fi range are increasing.
We need a solution as quickly as possible!!!

thank you for the quick reply.
Peter Stefanec.