Slesvig Envelope 10 Mark No Catalogue Value

Hello everybody
I have these 2 envelopes. I can not find the total value. Any ideas about why 10 Mark has no value at the catalogs?

Is this a philatelic creation intended to use all of the stamps in the issue, regarding of the rate?

These, are not cinderellas, but normal stamps. Do you know the difference?

Catalogue values for used on cover, generally, are not based on philatelic covers. The stamp, probably, has not been sold or offered genuinely used on cover, therefore, no price will be known.

As Cursus pointed out, you posted this in the forum for Cinderellas. You might want to ask a moderator to move it to a more appropriate forum.

The catalog values are for each stamp used rate appropriate. My guess is that if you researched rates at the time the 10 Mark had no real use when it came to letter mail.

As others stated, philatelic covers are not generally given a value.

I added Scott Special catalog image and all the others except 10 Mark has on cover values. 5 Mark is 135 USD
By that logic is 10 Mark 270 USD or more?
Somehow that envelope was actually sent to an address from Apenrade to Berlin. Seems not only a philatelic envelope. I really can't decide!

A question: How much would you pay for buying it?

A note: I know Cinderella, I did not realized

This cover is a philatelic use, and they are not rare. Fyns Frimærke Service in Denmark is one of the worlds most qualified dealers in Schleswig covers and they offer some philatelic covers with the 10 Mark for 150 to 250 Danish Kroner which ia about 20 to 30 US Dollars

Actually, logic might dictate that since the cover is philatelic, it will not even get near the USD 135 for the 5 Mark alone, as that would be the price for a 5 Mark stamp used to pay an existing tariff.

The addressee was a Berlin stamp dealer.

If you google "August Kalz" you will see lots of different philatelic covers sent to him at various addresses in Berlin.

This was a popular style of philatelic cover in Europe for many years.

@Murataxu, February 10 and March 14 are the dates when the votes were cast in the 2 Zones (see Michel catalog):



As mentioned before, it is a philatelic cover (does not correspond to the rates applicable in that period) and I think only the catalog values for used stamps can be taken into account.
I have the same series (Cancelled Flensburg March 14) which I suspect were cut from another philatelic cover :



I put them up for auction for 5 Euros a few weeks ago and I still don't have any bids,