8 year time cap for research students

Hi,
I am currently enrolled in an MPhil/PhD program and my visa is from September 2014 – January 2019. But mid-way I have decided to now just complete my MPhil and start with the PhD from another university. So I now complete my MPhil by April 2017 which is when my university will inform the home office to change my visa status as I would be done with my course (much earlier) and would then leave the country in a month or two. And then start a fresh PhD from another university from September 2017 the duration of which is 2 years.
I had a question on the 8 year time cap for research students. So far I did my -
MSc – visa 1 year 4 months
MPhil – visa used 2 years 6 months
Total use - 3 year 10 months
I would still technically have 4 years 2 months left on the time cap (if my understanding is correct) so if I apply for a fresh PhD program which is just 2 years as stated in my offer letter, will I get my student visa?
Even though my current visa is till 2019, as soon as my MPhil thesis is submitted in April, my university will inform the home office that I have completed my course and hence my visa date will be automatically be changed and I will I am assuming be given 2-3 months within which I wrap up and leave the country. So after that if I start my PhD fresh from another university with a new tier 4 sponsor and with full funding for a course duration of 2 years, I should be able to get my student visa right?
Any advice would be much appreciated!

pinkcarrot wrote:I would still technically have 4 years 2 months left on the time cap (if my understanding is correct) so if I apply for a fresh PhD program which is just 2 years as stated in my offer letter, will I get my student visa?

If you have a balance of 4 years 2 months remaining under the 8-year cap, and your new application is for a course of just two years, what is your concern about the cap exactly?