SNS.yaml: month and year conversion to seconds

SNS DAO SNS Project Governance
2

I found this piece of code in a foundation repo:

// A few helper constants for durations.
pub const ONE_DAY_SECONDS: u64 = 24 * 60 * 60;
pub const ONE_YEAR_SECONDS: u64 = (4 * 365 + 1) * ONE_DAY_SECONDS / 4;
pub const ONE_MONTH_SECONDS: u64 = ONE_YEAR_SECONDS / 12;

So it seems that 2629800 is used for a month in second and 31557600 for a year.

While it resolve most differences, but I still got issues with the dissolve delays.

Voting:
    minimum_dissolve_delay: 3 months

    VestingSchedule:
        interval: 6 months

However for such a distribution I got the correct amount of seconds:

          principal: g...
          stake: 1_500_000 tokens
          memo: 2
          dissolve_delay: 12 months
          vesting_period: 6 months

Is there somehow two different number of seconds for month and year used by the NNS governance?