notify that adres1 field is being checked

Hi, just a quick note about an issue that we have.
The checkout uses the 2 billing address fields, but apparantly MyParcel is going to check if the billing adres 1 field contains a number.
When there’s no billing adres field, there’s this notification: Vul een geldig factuuradres in. (fill in a correct invoice adres).

I get the good intention, but it just creates doubts. When using 2 adres fields, lot of people put the number in the second field. But that results in a notification, and people can not buy. And the notification is not really clear.

The only option is to unset the second adres field; as we did. But we are probably did lose a few sales because of this.

So, i guess MyParcel could be clearer here out of the box.