Same situation as yours. I told that I am issuing a WP for 1 year and if my passport expires earlier then the expiry date for WP will be same as expiration date of passport which means that you'll have to again apply for a renewal mid way.
This should be enough. If he/she doesn't agrees then mention that your health card also is valid until expiration of the WP and since it takes time for WP to arrive you can be without a health card for some time which is not good given how expensive this country is for medical expenses.
Hi, Thank you for the explanation. Do I need to write the reason down like a letter or I just have to go and tell them?