store setting - email with zoho email setting

Hi everyone

Good Day, i am not sure this is bug or the programming design/logic issue.
open cart version 2.0

when i configure the store settings, i use an email address abc@mydomain.com (hosted on zoho.com)
then i config mail settings with the instruction from zoho.com
SMTP protocol
-fxyz@mydomain.com (prefix -f before my email address)
ssl://smtp.zoho.com
password: *******
port 465
time 20

user cannot register, with some strange error, data not accepted, ehlo error, all poing to mail.php
it costed me a half day, googled, luckily found the solution,
option 1: the store contact and mail setting email address must use the same (all use abc@mydomain.com)
option 2: change the mail.php code, (attached screenshot)

i think usually we use different email address for these two different purpose, why we must use the same one
or if we must use the same email address, when wen config it in the admin page, the system should force/alert/warning the user, here you must use the same email account........

anyway, opencart is a great system and helped me a lot. saved me a lot $$$.
thanks.