Is your feature request related to a problem? Please describe.
The module procedures within an interface are declared as public along with the interface in field_manager and fm_util . For example,

public test
public test_integer
public test_real

interface  test
  module procedure test_integer
  module procedure test_real
end interface test 

The above should be

public test
interface  test
  module procedure test_integer
  module procedure test_real
end interface test 

Describe the solution you'd like
Cleanup of the interfaces in FMS

Describe alternatives you've considered

Additional context
In order to make FMS more perfect