A new starter is designed to draw X amount of amps to overcome the inertia of the armature when at rest and energize the starter drive.

As starter ages, and think about how much use a starter gets, it gets dirty with metal fillings, dirt etc which decreases the conductivity of the armature, thus making it draw more amps.

One way to test the starter amp draw can be done if you have a voltmeter with an inductive amp lead, or intrusive lead. Connect the VM to the (+) and (-) terminals of the battery, then clamp the inductive amp lead around, or insert the intrusive lead into the neg wire of the battery. Disable the ignition and crank the engine for about 15 seconds.
Watch the VM readings and the amp draw. Voltage should not drop below 9.6 Volts and amp draw should not exceed specs. THE SPECS FOR AMP DRAW is what I cannot find for your specific vehicle. What a pain...in fact I cannot find any specs for MB starter draw????

Good luck