Applied for Tier 2 visa on COS expiry day

Good day everyone, I made my Tier 2 visa appointment at the visa centre yesterday August 14. The visa payment was made by my employer last August 13. COS expiry is August15. My questions are:

1. Was the visa application considered as the date of the visa payment?
2. Does it matter if my COS is expiring while the visa process is ongoing?
3. Start date on COS is 1st September but the visa centre said visa applications made on that day will receive a result by 4th September. Is there anything to be done for this?

I am a bit worried that applying towards the end of my COS validity would be an issue. Thank you in advance!

Hi! Any response will be appreciated, thank you!