Schweiz - Privat-Ganzsache: why is double postage?

Swiss private postal stationery, It is Privat Ganzsache, 1900s, double postage, Swiss Horse Racing Federation,

Hello there,

Why is double postage? The year that started, stopped in that year?

thank you very much

Zitat von jmh67

Perhaps they needed stationery for heavier letters, and had extra postage added to existing envelopes.

-jmh

Hello there,

I don't need to be, and probably,

I need to know: the right knowledge