In civil actions arising under or by virtue of sections 393.410 to 393.510, and by virtue of the powers herein authorized, the statute of limitations shall not begin to run against any right or cause of action until the right or cause of action shall have accrued; provided that for the purposes of sections 393.410 to 393.510 the right or cause of action shall not be deemed to accrue when the wrong is done or the technical breach of contract or duty occurs, but when the damage resulting therefrom is sustained and is capable of ascertainment, and, if more than one item of damage, then the last item, so that all resulting damage may be recovered, and full and complete relief obtained.