NIC-Class 1A NIC

Sir I found a sentence in my study text that am unable to understand. It says that :

“the employment allowance is deducted form the the total class 1Employer’s NICs, not from the liability relating to one individual.”

So, I have two doubts pertaining to the aforementioned sentence. One, by employment allowance are they referring to employer’s class 1A NIC? Two, I used to think that employer’s class 1A NIC was deducted from his/her tax adjusted trading profits. But this sentence seems to suggest that its deducted from Employer class 1 NIC. So, now am confused.

Any help would be much appreciated.