[Rversteeg]

It is not so much a low ratio that your auto is stuck in, but the vacuum control system. The variomatic uses a combination of centrifugal force and vacuum in the front pulleys, spring load in the rear pulleys and traction force in the belts to shift up and down. Without vacuum assistance the auto stays quite long in a relatively lower ratios. Above say 35 - 40 mph the centrifugal force will be dominant over the belt pulling forces / spring load and shift to a higher ratio anyway. Fine for quick acceleration as you have maximum engine power, but a bit unnerving for normal driving.
Each front pulley drum contains a membrane. If engine vacuum is applied to one side of the membrane, it will cause the vario to shift up earlier. When braking or applying the descent brake feature, vacuum is applied to the other side of the membrane, causing the vario to shift to a lower ratio.
Quite often one or both membranes are leaking, resulting in late upshifting when acellerating normally. There are two rubber vacuum hoses running from the control switch to the variomatic. If you pull these hoses off from the control switch (mounted at the bulkhead) and blow in one of them, you should not be able to blow through. If you can blow through, at least one membrane is leaking.