[Seven_0]

In approaching the biblical prophetic year, the first task was to define its length, as determined by a comparison of related Scriptures containing similar time expressions. By subjecting these to a formal mathematical reasoning process, it was found that the prophetic year was equivalent to 360 days, and the prophetic month to 30 days.

Why would you need a prophetic year? God’s word and his creation are in perfect harmony. In fact we are told to look at creation to understand invisible things. In order to keep spring near the vernal equinox, every calendar has adjustments that must be used. Our years are not all the same length. God determined the length of a day, a month and a year when he put our solar system in motion. We know exactly how long each one is , we do not need to average various errors to find out

There is purpose in everything God does. You will never discover why God used the ratios that he used because you must have a 30 day month and a 360 day year to promote your error.

[BipolarBob]

God’s word and his creation are in perfect harmony.

No they aren't. There's no perfect harmony on this earth. We live in sin.
Now as to years, it used to be 360 days to a year but it is no more. That stopped when the Flood came. That changed a whole lot of things. We used to have a protective mist dome over the earth. No more. We now have clouds and rains instead of the mist watering the earth.
The earth has a wobble to it now. We have seasons and polar caps and mountains and canyons.
The earth today is very different from the beginning.