Unit change when writing mathematical expression as input

[nikal14]

Describe the bug
When writing a value in input: pressure, in for example "C-type Pressure Source", as a mathematical expression the unit changes to Pa without changing the input value.

To Reproduce

1. Add a C_type_Pressure_Source
2. Change the unit for "input: pressure" to MPa
3. Set the value of "input: pressure" to "20-7" or "20/100" and press apply, then ok
4. The unit for pressure will change back to Pa without changing the input value

Expected behavior
The component should keep the unit as stated by the user or change the input value with the correct prefix.