Express Postage Due Label

This express letter was sent on April 7 1934 from Schwechat, Austria to Zurich. On arrival in Zurich this label was attached to the reverse of the letter indicating a further 20 cents due for completion of the express delivery.

I surmise that this is a late application of distance-based rates for special deliveries. From January 1, 1921 until February 28, 1934 the express fee was 60 cents for deliveries up to 1-1/2 kilometers from the destination post office. If the address was beyond that distance, an additional 20 cents fee applied to each additional 1/2 kilometer. The additional distance fee was typically collected at the destination because the originating post office (in this case in Austria) would have no knowledge of the distance from the destination post office to the final address.

However, on March 1, 1934 the express fee was reduced to a flat 40 cents with no additional distance charges. Five weeks later, the new flat fees message doesn't seem to have made it to the delivery carrier in Zurich.