Nononono. The hitbox element flag is only the last 2 digits. Changing it to that entire thing droughboi listed will change lots of properties of the hitbox to whatever the original move was that flag set was copy/pasted from.
Element:
------YY
Important
The 2nd to last digit is SHARED with some other flag (possibly part of the SFX flag?), so the 1st digit will be combined with this other flag's digit. This other flag seems to always either be 0, 4, or 8
This other flag could look something like this:
(Part of SFX?):
------X-
or
-----XX-
or
----XXX-
So considering both of them, it could look like this:
------ZY
or
-----XZY
or
----XXZY
...with Z being the combined value of the 1st digit of the element and the last digit of that other flag. If the last 2 digits on the original flags are ------45, and the original element of the hitbox is Fire (05), then to make that instead have Darkness (13) the end of the flag would now be ------53, Normal Hit (00) would be ------40, Aura (15) ------55, etc. If it was originally Fire and the last 2 flag digits were ------85, Darkness would be ------93, Normal Hit ------80, Aura ------95.
This is an old elements list, but it seems to match what's used here as well for the one's I've seen:
YY
00 Hit
01 ?
02 Slash
03 Electric
04 Ice
05 Flame
06 Coin
07 Cape
08 Slip
09 Sleep
0A ?
0B Impale
0C Stun
0E Flower
0F ? (gives hitstun to some moves that don't normally have any)
10 ?
11 Slash 2
12 Hit 2
13 Darkness
14 Stun
15 Aura
16 Impale 2
17 Down
18 No Flinch
Again, don't overwrite the 2nd to last digit with the element's 1st digit. The 0 or 1 in the element is combined with the 2nd to last flag digit which is also shared with a different flag.