Need To Understand The Rate Of This Cover To Colombia Jyly 1-St 1992

Hi !

Please could you explain me the rate of this registered cover to Colombia july 1st 1992
Thanks +++
Kind Regards

Reg $4.40
Air 95c first ounce, 39c each additional 1/2 or fraction. Thus $2.12 for 2.5 ounces (noted on Douane)
Totals $6.52 and therefore overpaid by 40c.
Sender may have pre-stamped for 3 ounces with a 1c convenience overpayment.

Gerson's was a stamp and coin dealer. https://archive.org/stream/polkspor...ich_djvu.txt <<< EDIT use ctnl-F (search) with "gerson's"

Any upcharge for "Do Not Bend"? Nonstandard (non-machineable)?

Not in that time period and not for international mail.

I think "not in that time period" meant non-standard surcharge applied to over-1-ounce letters. 1-ounce letters were always subject domestically ever since July 15, 1979.
I'm not certain when over-1-ounce letters started being included, but likely with shape-based pricing that began May 14, 2007 (i.e., "letters" max out at 3.5 ounces; heavier is either large envelope or parcel based on other criteria).