Dear list,

in trying to solve the discrepancy between two different Gregorian dates (1310 AD in Kunjunni Raja 1958, but 1314 AD KSSC) given on the basis of the same "chronogram"
puṇyāṭavyām yatis syāt
denoting the Kali days according to the kaapayādi system of writing the numbers:
pu (1) - ṇyā (1) - ṭa (1)  - vyā (1)  - mya (1) - ti (6)- ssyaat (1) = 1611111

I came across the following useful on-line tool

which in this case gives the following precise date: 1310 February 19 (Wednesday).

I made some new testing on the basis of a few more Kunjunni Raja (1958)'s dates:

• p. 61 (Tantrasaṅgraha of Nīlakaṇṭha Somayājī): he  viṣṇo nihitaṃ ktsnaṃ =
1500 AD (he  vi-ṣṇo ni-hi-taṃ kṛ-tsnaṃ = 84508610)

Converter: 1500 April 1 (Sunday)

But  in K. Ramasubramanian, Tantrasaṅgraha of Nīlakaṇṭha Somayājī, 2011 , p. xxxvii, differently:
"(...) the Kali chronogram of the date of the commencement of the work, which turns out to be 1680548, and corresponds to Mina 26,4600 gatakali (elapsed Kali years) according to the Indian calendar, which corresponds to March 22, 1500 CE according to the Gregorian calendar"

• p. 129 (Prakryāsarvasva): "yatnaḥ phalaprasūḥ syāt  [and]  ktarāgarasodya
representing 1723201 (ya-tnaḥ-pha-la-pra-sū-ssyāt)
and 1723261  (kṛ-ta-rā-ga-ra-so-dya) respectively
... give the dates January and March of 1616 AD"

But converter : 1617 January 10 (Tuesday) and 1617 March 11 (Saturday) respectively

 • p. 130 : "the Nārāyaṇīya (completed) on 27th November 1586, expressed by the chronogram āyurārogyasaukhyam denoting the Kali date 1712210 ( ā-yu-rā-ro-gya-sau-khyam)"

But  converter : 1586 December 8 (Monday)

My question to the specialists of calendars/chronology : what explains these slight differences; is the on-line tool right or not in these cases ?

Best wishes