Can I switch again to Tier-2

[sancha]

In past, I have been on work permit visa from 2005 to 2006 (employer 1) then 2006 to 2009 (employer 2) afterwards on Tier-2 sponsor visa 2011 to 20013 (employer 3). Rest of the time I was either on Post study visa or student/Tier-4 visa. My work permit/tier-2 visa duration in total comes out more than 6 years (non-continuous). Currently I am on tier-4 visa which is valid for next three years. My current part time employer want me to full time and ready to give me CoS. Considering my previous work permit/tier-2 visa numbers and total duration (more than 6 years non-continuous), can I switch from tier-4 to tier - 2 now 4th time? In fact my ILR would be due end of this year on long term residency basis and I do not want any complications and therefore need your advices.
Thanks in advance