Jamieson, Fausset and Brown on Ezekiel 45:12

12. The standard weights were lost when the Chaldeans destroyed the temple. The threefold enumeration of shekels (twenty, twenty-five, fifteen) probably refers to coins of different value, representing respectively so many shekels, the three collectively making up a maneh. By weighing these together against the maneh, a test was afforded whether they severally had their proper weight: sixty shekels in all, containing one coin a fourth of the whole (fifteen shekels), another a third (twenty shekels), another a third and a twelfth (twenty-five shekels) [Menochius]. The Septuagint reads, "fifty shekels shall be your maneh."