Pledges round payments to whole dollars

Steps:

0. Go to a contact's Pledge tab
1. Enter a new pledge for $18 over 12 months ($1.50 per month)
2. Look at the payment schedule.

Expect:

Twelve payments of $1.50

Actual:

Eleven payments of $2.00 and one payment of $-4.00.

Notes:

I reproduced this on the demo site. We have at least one pledge that can not be entered as a result of this.