[Galaxy S 4 i9505 Original Android Development] Bejda:
Sure, usually aosp roms use:

format("ext4", "EMMC", "/dev/block/platform/msm_sdcc.1/by-name/system", "0", "/system")

but, on Touchwiz customs generally,it can be one of the two ways you mentioned.

I updated my primary Echoe rom yesterday which updater-script was:

ui_print("*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_");
ui_print(" Galaxy S4 Echoe Rom v15 ");
ui_print(" UNOFFICIAL ANDROID 4.4.2 ");
ui_print(" I9505XXUFNAD Samsung Firmware Base ");
ui_print(" ***Created by the ECHOE TEAM*** ");
ui_print("*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_");

ui_print("Wiping Cache ...");
ui_print("*************************");
mount("ext4", "EMMC", "/dev/block/mmcblk0p18", "/cache");
delete_recursive("/cache");

ui_print("Wiping Dalvik Cache ...");
ui_print("*************************");
mount("ext4", "EMMC", "/dev/block/mmcblk0p29", "/data");
delete_recursive("/data/dalvik-cache");

if
file_getprop("/tmp/aroma-data/wipe.prop","selected.0") == "1"
then
ui_print("Wiping Data ...");
ui_print("*************************");
package_extract_file("EchoeExtras/scripts/wipedata", "/tmp/wipedata.sh");
package_extract_file("EchoeExtras/scripts/bash", "/tmp/bash");
set_perm(0, 0, 0777, "/tmp/wipedata.sh");
set_perm(0, 0, 0777, "/tmp/bash");
run_program("/tmp/wipedata.sh");
endif;

ui_print("Deleting Current System ...");
ui_print("*************************");
mount("ext4", "EMMC", "/dev/block/mmcblk0p16", "/system");
delete_recursive("/system");

ui_print("Installing System...");
ui_print("*************************");
package_extract_dir("system", "/system");

######## BLOAT ########

if
file_getprop("/tmp/aroma-data/bloat.prop","item.0.1")
..............

Once edited,it was like this:

ui_print("*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_");
ui_print(" Galaxy S4 Echoe Rom v15 ");
ui_print(" UNOFFICIAL ANDROID 4.4.2 ");
ui_print(" I9505XXUFNAD Samsung Firmware Base ");
ui_print(" ***Created by the ECHOE TEAM*** ");

if
file_getprop("/tmp/aroma-data/wipe.prop","selected.0") == "1"
then
ui_print("Wiping Data ...");
ui_print("*************************");
package_extract_file("EchoeExtras/scripts/wipedata", "/tmp/wipedata.sh");
package_extract_file("EchoeExtras/scripts/bash", "/tmp/bash");
set_perm(0, 0, 0777, "/tmp/wipedata.sh");
set_perm(0, 0, 0777, "/tmp/bash");
run_program("/tmp/wipedata.sh");
endif;

ui_print("Deleting Current System ...");
ui_print("*************************");
mount("ext4", "EMMC", "/dev/block/mmcblk0p16", "/system");

ui_print("Installing System...");
ui_print("*************************");
package_extract_dir("system", "/system");

######## BLOAT ########

if
file_getprop("/tmp/aroma-data/bloat.prop","item.0.1")
................

As you can see i removed wipe /cache part otherwise it would have delete all my multislot* rom's systems (you can keep the mount /cache part and just remove delete recursive if you wish.

I removed also wipe dalvik-cache,not mandatory you can keep the whole thing but I intended to make a clean install anyway by using dualboot utility zip to wipe primary cache,dalvik-cache and /data.

And of course i didn't use the wipe data options from the franzyroy themed aroma installer ;) otherwise it would have delete all of my dual and multirom's data's (used dualboot utility to wipe primary rom /data then)

+ to not have to reflash your secondary rom no matter updater-script edit use this:

"Download the two zips here and flash the appropriate one before and after the primary ROM's zip: http://d-h.st/users/chenxiaolong/?fld_id=30845#files "

Switched to Philz 6.09.2 just to flash Echoe without errors and all went fine :)