Not really. In the past I used a single 11 element yagi on both SSB and FM with good results (keep in mind that on 2m, SSB uses horizontal polarization and FM uses vertical by convention). The trick was setting it at a 45 degree angle. At that point the loss was probably about 3 dB for either mode, but if it was a few degrees one way or the other the effect was quite noticeable on the opposite mode. No, it's not ideal, but it will work, so 25 degrees isn't much of a problem. After all, mobile antennas will often have some off angles depending on terrain and mounting on the vehicle and they work fine so anything within 45 degrees of vertical should work well.
