AE Frame Blending for Reversed layer

Hi,
I just want to know that is there any difference in the processing of frame blending when the layer is reversed.

I have a layer, by default the stretch is 100%, i enabled Frame Blending for that layer. Opacity for the blending frame comes as follows,
For 1st Frame - 5.5%
For 2nd Frame - 89%
For 3rd Frame - 5.5%

But when i reverse the layer, it comes as
For 1st Frame - 4%
For 2nd Frame - 87%
For 3rd Frame - 9%

In both the case stretch is 100%, in second case it is -100% as it is reversed.
My doubt is why is the opacity for the frames is different?

I am not having any problem with any conversion.
My doubt is why should be the Frame Blending result different when we reverse the movie...

I created a movie in a After Effect with Numbers from 1 - 10 which goes from left to right. Render that movie as RGBA and import that movie.

Now add a layer for the imported source.Enable frame Blending and seek to frame number 2 of Composition.

As Frame blending is enabled while rendering frame 2 , it will use frame 1, 2 and 3, and blend those frames with opacity of 5.5% for frame 1, 89% of frame 2 and 5.5% of frame 3. It follows the same pattern of blending for all the frames except the first and last frame.

Now my doubt is when i reverse the layer, the opacity considered for blending is changing to 3%, 87% and 9%...