Creating a Plan with the EE share is a flat amount and the deductions scaled for 10/12 Months

In the event that you need to link Employee Contributions to a Healthplan you will do so through a Contribution Group. 

This will be done through a Lookup Table Contribution Group. Make sure the box for "Automatically Scale the Then Add Flat Amt Amount to 10/12 Term Employees" is checked in order to scale the plans appropriately. 

On the Lookup table as long as there are no percentages you will follow this exact setup where you have PREMIUM selected, all 0's in the % boxes and then your flat amounts will be the Employee Contributions.