delboytwo:
reading the above it still looks like 56 hours and a 90 hour spread
You are falling into the trap of assuming you could only do six shifts in a week, you could do more than that with a weekly rest during the week. Under the old regs it was legally possible to do the following.
Start at 00:00 Monday
Drive 10 hours
9 hours rest
Drive 10 hours
9 hours rest
Drive 9 hours
9 hours rest
Drive 9 hours
11 hours rest
Drive 9 hours
11 hours rest
Drive 9 hours
24-hour weekly rest away from base.
Drive 9 hours
11 hours rest
Continue the 9 drive 11 rest pattern until 24:00 Sunday and all breaks are taken during each shift as required.
By the time the new week started you would have legally done a little over 70 hours driving with a weekly rest taken after no more than six daily driving periods as required. I can’t remember the exact number but I think it was something like 72 or 73 hours. It would be very unlikely to happen to that extreme as it leaves no time for anything else such as fuelling, checks, hooking trailers etc but the point was it was legally possible so a weekly limit of 56 hours was introduced to prevent it. Even allowing say 15 minutes a shift for checks your driving would be still well in excess of 56 hours for the week. I’ve done weeks in the past with more than 56 hours driving in them going to the south of Spain or Italy where for about 3 days in each direction you do little more than drive, break, drive, rest, drive, break drive, rest etc.
As you like the quiz questions here’s one for you. 
Under the old regs what was the maximum driving possible in six shifts?
Under the changed regs what is the maximum driving possible in six shifts?
Not as complicated as Mike’s questions but an easy one for a Monday.