If so, should such wage be paid for the entire project or only for the part of the project over $75,000?
Section 290.230.5(1), exempts projects from the requirements of the new law where either the engineer's estimate or the bid accepted by the public body is less than $75,000 total. Only if a contract is subject to a change order (Sec. 290.230.7) would the amount above $75,000 be subject to the prevailing wage or PWCMW.
However, Sec. 290.220 and 290.230 set forth the public policy intent that no contractor will be allowed to pay less than either the prevailing wage or the PWCMW wage where appropriate. When read together, these statutes would appear to make it the duty of both parties to seek a change order if cost overruns pushed the cost of the project over the $75,000 limit. To avoid doing so might demonstrate intent to avoid the law.
However, DOLIR is not able to provide legal guidance on individual contracts and how they might interact with Missouri law.