The round punch-marked coins have been shown to precede chronologically the "bent bars", also minted under Achaemenid rule from Bactria to the Punjab.
The practice of using unmarked silver bars for currency is known from the Iranian plateau and seems to have been current in Central Asia under the Achaemenid Empire.
 The bent bars are believed to have been derived from that practice, representing "a marriage between Greek coinage and Iranian bar currency".

The short "bars with punch-marks" (28x15mm) discovered in Chaman Hazouri are attributed to the Paropamisadae by Bopearachchi.
Their design uses two circular symbols punched at each end of one face of the bar.
These bent bars are clearly reminiscent of later punch-marked Indian types, which use several of the designs of these coins "of a new kind".
The "long bars" with punch marks (42x10mm), of which none were found in the Kabul hoard, are attributed to the area of Gandhara, as well as in the Bhir Mound hoard in Taxila.

Development of Indian punch-marked coins
According to Joe Cribb the earliest punched-marked bent-bars are found in the northwest of the continent, and their simple designs was then adopted in the Gangetic plains, before designs evolved there towards the usage of more numerous punches on each coin.
This is also proven by the fact that the Gangetic plains have no known coin designs anterior to their simple punch-marked bars, whereas the Kabul/Gandhara punch-marked bars were preceded there by the round punch-marked coins with symbols, minted under the Achaemenids.

Daniel Schlumberger too considers probable that punch-marked bars, similar to the many punch-marked bars found in northwestern India, initially originated in the Achaemenid Empire, rather than in the Indian heartland:
“The punch-marked bars were up to now considered to be Indian (...) However the weight standard is considered by some expert to be Persian, and now that we see them also being uncovered in the soil of Afghanistan, we must take into account the possibility that their country of origin should not be sought beyond the Indus, but rather in the oriental provinces of the Achaemenid Empire"
— Daniel Schlumberger, quoted from Trésors Monétaires, p.42.
The round punch-marked coins have been shown to precede chronologically the "bent bars", also minted under Achaemenid rule from Bactria to the Punjab. The practice of using unmarked silver bars for currency is known from the Iranian plateau and seems to have been current in Central Asia under the Achaemenid Empire.  The bent bars are believed to have been derived from that practice, representing "a marriage between Greek coinage and Iranian bar currency".
The short "bars with punch-marks" (28x15mm) discovered in Chaman Hazouri are attributed to the Paropamisadae by Bopearachchi. Their design uses two circular symbols punched at each end of one face of the bar. These bent bars are clearly reminiscent of later punch-marked Indian types, which use several of the designs of these coins "of a new kind". The "long bars" with punch marks (42x10mm), of which none were found in the Kabul hoard, are attributed to the area of Gandhara, as well as in the Bhir Mound hoard in Taxila.
Development of Indian punch-marked coins
According to Joe Cribb the earliest punched-marked bent-bars are found in the northwest of the continent, and their simple designs was then adopted in the Gangetic plains, before designs evolved there towards the usage of more numerous punches on each coin. This is also proven by the fact that the Gangetic plains have no known coin designs anterior to their simple punch-marked bars, whereas the Kabul/Gandhara punch-marked bars were preceded there by the round punch-marked coins with symbols, minted under the Achaemenids.
Daniel Schlumberger too considers probable that punch-marked bars, similar to the many punch-marked bars found in northwestern India, initially originated in the Achaemenid Empire, rather than in the Indian heartland:
“The punch-marked bars were up to now considered to be Indian (...) However the weight standard is considered by some expert to be Persian, and now that we see them also being uncovered in the soil of Afghanistan, we must take into account the possibility that their country of origin should not be sought beyond the Indus, but rather in the oriental provinces of the Achaemenid Empire"
— Daniel Schlumberger, quoted from Trésors Monétaires, p.42.
Kabul hoard