Interesting family!! Olav O. Bjelland appears to have been married first to Gislaug Olsdtr (1829-1864). After she died he married Lisbet Olsdtr (1820-?). Gislaug and Lisbet were sisters, both the daughters of Olav Larsson Fugleberg/Bringedal (1781-1870) and Guro Torsdotter Bringedal (1787-?). The girls had several other siblings, among them Lars (1811-1846), Tor (1813-?), Jens (1816-?), Guro (1831-?) and three others that didn't survive to be more than 5 years old.
(Source, pp. 35-36 of Erling Vaage's "Kvinnherad 4 - Husnes - Gards- og ættesoga")
I'll try to get time to check what I can for the Bjelland farm later this evening (It is in the same book). But if Lars was born in 1865 - then Lisbet was his mother. But he had the same maternal grandparents as his siblings.....
When in doubt about dates, check the original church records!! It really isn't that difficult.