Servomyces is simply dead yeast. Prior to being killed, it was fed micronutrients which have been stored in the yeast. There's no harm pitching more into your starter, assuming you then later pitch to 5 gallons or more. If your starter yeast don't use all the nutrients, your main brew certainly will, so there's no harm pitching the entire capsule.

The White Labs FAQ says this about Servomyces

> Servo is yeast and is propagated in a micronutrient rich environment
> then, and is killed off prior to packaging. Boiling incorporates the
> Servo into the wort. The benefit of Servo is that micronutrients, e.g.
> zinc, are able to pass through its cell walls to your live yeast cell,
> thereby delivering the micronutrients without toxicity. Because this
> system is so effective in eliminating autolysis and improving the
> health of your yeast, it should be used in every batch.