is it necessary to focus on actually performing new 1 rep max lifts as you are progressing with say 80% loads.? should you just concentrate on adding weight every week and not worry about it.?

No it's not. In fact, it is very easy to get burntout on singles. Triples all the way!

Lifting 90% or more of your max for more then 2 weeks can actually be counterproductive of your goals. Take 80% of your max, do whatever set/rep scheme you wan't and add 2.5% every week. Example:

Week 1: 80%
Week 2: 82.5%
Week 3: 85%
Week 4: 87.5%
Week 5: 90%

Then Deload