Performance of array redimensioning in Natural

As I found out totay, the performance of redimensioning an array in Natural largely depends on the statement you use. I compared RESIZEand EXPAND and found out, that RESIZE is more than two times slower than EXPAND. With bigger arrays, RESIZE may even be up to 20 times more slowly than EXPAND!

Unfortunately, the documentation for the two statements is almost identical (see RESIZE and EXPAND). So there is no hint on why the performance is so drastically different.

Example program:

DEFINE DATA
*
LOCAL
01 #I (N8)
01 #ARR (A8/1:*)
01 #START (T)
01 #END (T)
01 #TIME (T)
01 #N (N8)
END-DEFINE
*
#N := 100000
*
#START := *TIMN
*
REDUCE ARRAY #ARR TO 0
FOR #I 1 #N
  RESIZE ARRAY #ARR TO (1:#I)
END-FOR
*
#END := *TIMN
#TIME := #END - #START
WRITE 'RESIZE' #TIME
*
#START := *TIMN
*
REDUCE ARRAY #ARR TO 0
FOR #I 1 #N
  EXPAND ARRAY #ARR TO (1:#I)
END-FOR
*
#END := *TIMN
#TIME := #END - #START
WRITE 'EXPAND' #TIME
*
END

Result:

RESIZE 00:00:11
EXPAND 00:00:04

If I use a more realistic array (that resembles a real database row), the result is even more obvious:

01 #ARR (1:*)
  02 #A1 (A8)
  02 #A2 (N8)
  02 #A3 (A) DYNAMIC
  02 #A4 (L)
  02 #A5 (N12,7)
  02 #A6 (A100)
  02 #A7 (A1000)

Result (after only 10,000 iterations):

RESIZE 00:01:04
EXPAND 00:00:18

And another result (after 20,000 iterations):

RESIZE 01:25:02
EXPAND 00:03:23