The scanlation posted above is inaccurate.
The translation from VIZ states that the Cultivars/Saibaimen have a PL "over" 1,200, and are equal to Raditz:
And even the Japanese manga merely states that the Saibaimen "rival" Raditz in power:
[edit]
CD posted the quote above.
So yeah, the Daizenshuu's PL of 1,500 makes sense, imo. That's why PLs in the 1,300+ range were enough to injure Raditz--or potentially even kill him, if they were piercing-type attacks(like Piccolo's SBC.)
Number crunching. So much number crunching.
They're close enough that the ki difference is mostly negligible and Yamcha's performance against the Saibaman(who are pretty clearly below Raditz if only because the Saiyan is a more experienced fight) shows him as being on that level. And on roughly even ground, Yamcha will win.