Hi Pedro,
If both the instances of P_ORGIN are assigned in 1 user, then both the set of values will be applicable to both the t-codes. So, you can use one instance, instead of 2.
Therefore, you need to exclude W(write authorizations) in P_PERNR.
Generally, For the Infotypes, for which you would need Maintain access, you would also need Display access, for the same.
Regards
Plaban