removeAEC.LSP and UNITS change problem

after using the following lsp dwg units revert to the value from the time the dwg was created even though the -dwgunits was set to new value before.

How to avoid that?

if dwg was created in inches, changed to cm using -dwgunits

it will change back to inches after the frollowing code on autocad 2018 and 2019... here is the code:

(defun gc:GetDictEntries (dict / result)
(and (= (type dict) 'ENAME) (setq dict (entget dict)))
(while
(setq dict (vl-member-if (function (lambda (x) (= (car x) 3))) (cdr dict)))
(setq result (cons (cons (cdar dict) (cdadr dict)) result))
)
(reverse result)
)

;; delete all AEC*
(defun c:removeAEC ()
(foreach dict (gc:GetDictEntries (namedobjdict))
(if (wcmatch (car dict) "*AEC*")
(foreach entry (gc:GetDictEntries (cdr dict))
(entdel (cdr entry))
)
(entdel (cdr dict))
);fin if
)
(princ)
);fin defun