alpha channel

im hoping someone can shed some light on this becuase its makes no sense to me. im creating a game in C# and have just successfully made a fade in / fade out effect using directX sprite calls and changing the alpha value. it works perfectly, but becuase I have an animation (which the frames are stored in a tileset bitmap) I have to make two calls, one to Sprite.Draw and one to Sprite.Draw2D. I use the sprite.Draw function b/c it lets me specify the rectangle to draw within the tileset. Now heres the problem..... The rates of the fading are not the same. The calls are back to back, so the m_Alpha value doesnt change, but the animated rectangle fades in slower than the non animated section. for example, I do a call to BGSprite.Draw2D(m_Texture, new Point(0, 0), 0f, new Point(0, 0), Color.FromArgb(m_Alpha, Color.White)); BGSprite.Draw(m_Texture, m_Options[OptionIndex].GetCurrentCoordinates(), Vector3.Empty, m_OptionCoords, Color.FromArgb(m_Alpha, Color.White)); i hope you understand my problem. i have no idea why its doing what it does. Thanks!