Well I've spent some time trying to answer and now the thread has moved on somewhat: I'll post it anyway!
You are using a mixed insulin.
Humulin M3 30/70 is premixed containing a 70% intermediate acting insulin and 30% short acting.
This one (m3) takes a time to start working so normally taken some time (say 30 min) before a meal
http://www.netdoctor.co.uk/diabetes/medicines/humulin-m3.html
Novomix 30 is a premix containing 70% intermediate and 30% rapid acting.
The rapid part of this works more quickly so is normally taken just before or even just after a meal
http://www.netdoctor.co.uk/diabetes/medicines/novomix-30.html
Most often people are prescribed these insulins twice a day at breakfast and dinner but if prescribed 3 times a day the expectation is that it is before each of 3 meals.
These diagrams may help you
Images from
http://www.betapresentations.com/InsulinMar07b.pdf
You can see (just) that the rapid insulin in the novomix works a bit faster than the short acting in M3, otherwise the action of the basal is similar
The use of these insulins is based upon both eating at regular times and regular amounts. This requires consistent carbohydrate intake because if you reduce insulin because you've stopped eating carbohydrates you will not have sufficient to cover your basal needs. If you don't reduce the insulin then you would hypo. It is not going to work with a on /off fasting schedule and it's no wonder that you are getting very up and down levels.
I did write about how to adjust these insulins but for the moment I've edited it out.
There are more flexible insulin regimes which many of us use but they involve 2 insulins and more injections