I think the short answer to your question is there is no hard and fast rule prohibiting them in a commercial relationship. Late fees and interest are permissible in the commercial context but the amounts must be reasonable. The late fee should bear some reasonable relationship to the costs incurred by having to collect and/or take other enforcement action. Similarly, interest may be limited by state usury laws if applicable, but otherwise the amount needs to be reasonable and should be a penalty.
In a commercial lease, late fees are presumptively valid. A tenant can still show that they bear no reasonable relation to estimated damages in case of a late payment.