Depending on how you exactly flushed the system, you may have a shade less than a 50% mix. Otherwise I think you're okay. Use an inexpensive coolant strength tester to find out the exact strength of your coolant.

After flushing, it's hard to drain all of the water, so some pure water remained in the cooling system before refilling. Also, flushing doesn't remove the coolant in some passages, like the heater core and water pump. Both of these things leave you less than 10 liters for refilling.

During flushing I run the heater and engine so all coolant is removed, including the overflow. Then drain as much water out of the system as possible. Refill half the capacity with antifreeze, and top off with water. This should guarantee a 50% mix.

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95 E320 Cabriolet, 169K