Honestly, I don't know what to tell you. I would say no, specially if you do have the 15k - if you showed Ontario that you had 15k, and then by the time you get your ITA, you're not showing anything, it might look weird? I don't know.
If it doesn't change your score, go ahead and change anything you need to change - as long as you don't make *censored word* up, that is
If it makes you feel better, I didn't have any issues while submitting my application or filling the forms.
Just the classics - copies of ID/passport documents, proof of funds, proof of medical, experience letters from past employers, police clearances, .. I think that's it. And a slot for your Letter of Explanation. Later on you will have to upload or send them a Schedule 4 and possibly a copy of your nomination as well. I added it to my Letter of Explanation, but I wouldn't be surprised if they still ask me to send it to them again. So yeah, what you said ^^ They also ask you to fill forms with your addresses, your personal history and your travels over the past 10 years. I know it took a while for me to get it done, so if you want to start working on your application, this is something that you can do!
I did get it by mail, not too sure how long it took as I was away on holidays, sorry :/