Dear dawar098 its not the problem of your LNB setting. So keep the LNB setting as it was previously, i.e.-
You can get all TPs of NSS 6 together just with this LNB setting,
When you changed the Low frequency to 11300 you should have the signal of frequency, 12534 Hor 27500 but not the channels which are originally available on this frequency. After scan this frequency you should get the channels which are available on frequency, 10974 Hor 27500.
You can get all channels which are originally available on frequency 12534 just with above mention LNB setting.
So keep your previous LNB setting and try to put frequency 12532 or 12536 instead of 12534, You will get the signals and the original channels of this TP if your dish alignment is correct.