Confusing Definitions: involuntary manslaughter and manslaughter.

Okay, so I was wondering what the real difference between involuntary manslaughter and manslaughter is.

Involuntary manslaughter: The unintentional killing of another while in the commission of an unlawful act or while in the commission of a reckless act.

Manslaughter: The unlawful killing of one human being by another without malice aforethought.

These are two different counts that a person can get charged with, correct?  So I assume that an example of involuntary would be if you were driving drunk and you killed someone in another car because you were in the commission of a "reckless and unlawful act," but what if you got in an accident and killed someone while not drunk? And it was totally not expected?  Could you be charged with manslaughter since you fit under the definition of "without malice aforethought" and you weren't doing anything reckless or unlawful?

Also, which is the lesser of the two sentences?

Whether someone is charged with voluntary of involuntary manslaughter is up to the State Attorney's Office - it's that simple.  They use guidelines, then put in variables.  Involuntary is when the act was committed, but there was no intent to commit the act, however, a person's behavior (drinking, rage, wrecklessness) contributed to the act happening.

The State Attorney's Office may also lower a charge in either a plea bargain; or to be sure it meets the State's standards for the charge and is sure to get a favorable verdict (meaning in voluntary it will probably get a favorable verddict; but involuntary, it is sure to get a favorable verdict, then the SA will go with involuntary.

In involuntary, the jail or prison term is usually far less than with favorable.