Receiving the rewards for fasting on virtuous days

Q: I made a vow that if I commit a certain sin I will fast for 3 consecutive days. Unfortunately I fell in to this sin many times after so I have 27 fasts to keep. If I fast with the intention of these fasts on days that are virtuous to fast like the first 9 days of Zul HIjjah, 13 14 15 of each month will I receive the thawaab that comes with normally fasting on these days or will only my vow be carried out?

Qadha Salaah after Asr

Q: With the Mercy of Allah, I have recently starting reading all my qadhaa salaah that i have missed since i became baaligh, this being a few years of salaah. I am able to read my fajr qadhaa before leaving for work, then my zohr qadhaa after performing zohr salaah, magribh qadhaa after magribh and esha after esha salaah. I have not been able to fit in my asr salaah as I am aware that one cannot perform any salaah afer asr. However, I have been advised, that if i am performing my qadhaa salaah then i can perform it after asr. Is this correct or permissable?