correcting spelling can be touchy, you handled it well.
I recall well into my 20's being corrected by my accountant re "stationary"
I felt it better to endure momentary embarrassment, than long time ignorance.
Fiscal use... stamps employed as revenue usage.
(Perhaps part of a "commercial Overprint" -business imprint from commercial papers)
Your example has rings around the Value numerals,
The variety has them missing
Source : Mr. Tony Clayton Italian Philatelist.
(I have yet to find this variety)