It looks like Snopes did some digging and couldn't find any evidence they consider reliable. After reading the arguments, I have to agree with Snopes. The evidence for quotas is dependent entirely on the word of the accusers. Planned parenthood is a commonly used bogeyman for right wing groups. This accusation seems like the kind of thing people vehemently opposed to abortion might make up.
In the Snopes article, Planned Parenthood denies quotas. "We contacted Planned Parenthood about the claims, and a spokesperson reiterated that Planned Parenthood maintains no “quotas” for abortions or any of the other services they provide. Another longtime employee of Planned Parenthood whom we spoke had never heard of abortion quotas throughout the duration of her tenure with the organization."