S-off to S-on (Purple tint) Are correct these steps?

Hi , I have a One (M7) and I'm planning to send it back to HTC in order to fix the purple tint problem.
I'm S-off and I want to Lock the bootloader and returning to Stock + S-on.

I'll follow these steps from http://forum.xda-developers.com/show....php?t=2541082 Post #4 but i have doubts marked in blue

Step 0: -not in the previous thread link- I have hboot 1.57. Do I have to move to 1.44 ?

Step 1: let's get rid of TAMPERED (if it's there) and set you back to LOCKED (not relocked)
and confirm no TAMPERED and LOCKED status. (I have UNLOCKED status, so I'm only have to set it to LOCKED, isn't it?)


Step 2: Flash your RUU.zip
Download your MID & CID compatible RUU.zip: http://www.htc1guru.com/downloads/ruu-zip-downloads/
Rename the downloaded file to ruu.zip (careful about ruu.zip.zip in Windows)
(My mid is PN0710000 and cid= HTC__304 so I'll flash
RUU+Zip+M7_UL_JB_50_HTC_Europe_1.28.401.7_Radio_4A .13.3231.27_10.31.1131.05_release_310878_signed)
Do I need first to flash a stock splash?. Currently, I have Maximus 53 HD rom installed (with its own splash bootloader).


Step 3: if YOU decide to go S-On (Note: this should only be done for warranty or selling the phone, it is not needed for OTAs)
fastboot oem writesecureflag 3
( with 1.44 hboot, doesn't exist the possibility of a TEMPERED boot loop, Is it right?)

Thx in advance.