Knots are used all over the world as a memory aid. I think it is meant that we should use the information shown by 5 respectively 4 knots.

Could the meaning be that we should count 4 * 31 + 5 * 30 = 124 + 150 = 274?

In my own solar calendar for 2004 I can count 7 * 31 + 4 * 30 + 1 * 29 = 217 + 120 + 29 = 366, which is OK because 2004 was a leap year.

In an ordinary year we need to increase 274 in the Phaistos disc with 91 to reach 365. There seems to be one quarter missing. I think one possible explanation is that at that early date they did not regard the year as having two seasons (or four as we do). Instead they regarded the missing quarter as outside their sacred year. Perhaps the weather during one quarter of the year made agriculture and fishing impossible.

The Roman calendar before Julius Ceasar seems to have had ten months only. Otherwise, why should December, the last month of the year, be called like that? The latin word 'decem' means 10.