4. Section 10 of the Principal Act is amended—
(a) by omitting from paragraph (1) (a) “most”;
(b) by omitting from paragraph (1) (b) “most” (first occurring);
(c) by omitting from subsection (1) “most recently determined or redetermined” (last occurring) and substituting “then recently determined or redetermined”; and
(d) by adding at the end the following subsection:
“(3) In subsection (1), a reference to a recent determination or redetermination of the unimproved value of a parcel of land (not being a reference to the most recent) shall be read as a reference to any of the last 3 determinations or redeterminations of that parcel.”.