All layers earlier than the two 1-year layers defined will be merged into a single layer, but that will be considerably more than 2 years ago.
When you run the merge today (October 14, 2015), here's how QRecall will calculate your merge.
You're keeping the most recent 7 days, so any and all layers captured after Oct 7 will be left as they are.
In the next tier, you have 90 day layers. QRecall starts at Oct 7 and looks backwards for the first full day, which is Oct 6. All layers captured on Oct 6 will be merged into a single layer. It repeats this for the remaining 89 day layers:
Day 90: Oct 6, 2015
Day 89: Oct 5, 2015
Day 88: Oct 4, 2015
...
Day 1: July 9, 2015
Your next tier has 52 week layers. Starting with July 9, 2015 QRecall looks for the nearest full week, which ended on Saturday July 4, 2015. All layers captured between Sunday June 28, 2015 and Saturday July 4, 2015 will be merged into a single layer. This repeats for the previous 51 weeks:
Week 52: Sat June 28, 2015 - Sun July 5, 2015
Week 51: Sat June 21, 2015 - Sun June 27, 2015
Week 50: Sat June 14, 2015 - Sun June 20, 2015
...
Week 1: Sat June 29, 2014 - Sun July 5, 2014
The next tier keeps 12 month layers. Again, started at the beginning of the last tier (June 29, 2014), QRecall searches backwards for the first full month, which is May, 2014.
Month 12: May, 2014
Month 11: April, 2014
Month 10: March, 2014
...
Month 1: June, 2013
Finally, you have 2 year layers. These will start on the previous full year before June, 2013:
Year 2: 2012
Year 1: 2011
Finally, all layers captured before January 1, 2011 will be merged into a single layer.
Every thing else: 2006(*) - 2010
I hope that helps.
(*) Why 2006? Because that was the first public release of QRecall. Obviously, you can't have any layers before that.