@LenaH
Also, your response will be applicable if you are using the same portion of the house for 2 different Schedule C. In that case the same 33% is used for both business. So, overall use of home is 33%. In this case, you will need to split the property tax for 2 Sch Cs. So, the overall deduction is still 33% and you are not double dipping. However, in @marc1974 case, there are 2 different areas.
May be this is the issue causing error in Turbo tax where it is adding all the property tax entered in form 8829 assuming all schedule C are using same part of the house.
In either case, the SALT does not apply for Sch C.
