When single claim of lien sufficient.

All labor performed, and materials and services furnished, by any person entitled to a lien under this part shall, for the purposes of this part, be considered to have been performed or furnished under a single contract, regardless of whether or not the same was performed or furnished at different times or on separate orders. However, no more than 90 days shall have elapsed between the date of performance of such labor or the date of furnishing such materials or services and the date on which labor is next performed or materials or services are next furnished.