NSW Meaning and correct interpretation of word "FROM" in relation to periods expressed in months

[Vadim]

G'day,

I will appreciate if anyone let me know if [an event on 30 September] is included or not included into [a period of 3 months] in the sentence below according to English language rules and Australian legislation.

[a period of 3 months] FROM [an event on 30 September] ends on 30 December

Thank you in advance
Vadim

 

[Rob Legat - SBPL]

We already did this didn't we?