Till you get PER, you can consider the date when the file was delivered .. but if the date in your ECAS first line is different, then you should consider that date as application date ...
Most of the times both the dates are same... but sometimes they may differ .. it really happened to one of the senior most forumity CanOl .. Good thing is that his file didnt miss in between and he got PER by God's grace
Below is his post from archives for your quick reference
on: December 30, 2014, 10:57:35 am
Hey guys,
Hope you guys are doing fine. Just an update from my side which I thought I should give.
Just returned from Goa. Checked my email and saw that CIC had replied to my query dated 1st Nov on 24th Dec. The email says that my application was recd by them on 20th Oct (though my courier tracking says that application was recd by DAN on 2nd Sept). The email further says that my application is under initial processing. Cheesy Cheesy
I had honestly lost all hope for PER, as there has been no status on my application, but looking at this email, I am really happy, though effectively, my application is delayed by around 48 days.
Will get back to the forum in 2-3 days time.
All the best everyone.