I had a change of income and have 2 1095-A forms and I'm having trouble getting the SLCSP entered on the first one because it is zero

[iamtestpass_sms_123]

Yes, if you have a 1095-A form (or two), you need to enter the monthly premium SLCSP in Part III Column B, for every month, even if your form does not have this value in it.  

If you need, this link can help you find the amount to enter:  https://ttlc.intuit.com/replies/5286421