R.I. Gen. Laws § 5-93-12

If a solar retailer does not, at the time of providing a standard disclosure form, have exact cost information required to be included in the standard disclosure form, pursuant to this chapter, the retailer may make a good-faith estimate of that information, if the solar retailer clearly indicates that the information is an estimate and provides the basis for the estimate. If the solar retailer’s final cost assessment differs from previously provided estimates, the retailer shall provide a new and complete standard disclosure form including itemization of cost differences from the previous estimate.