Weghted Prediction for P-frames - nonstandard values

[xyzuvw]

According to documentation the option "Weghted Prediction for P-frames" can accept the following values:
1. Disabled,
2. Blind Offset,
3. Smart Mode.

But the corresponding combo-box in Avidemux 2.6.1 offers other values:
A. Disabled
B. Weighted References
C. Weighted References + Duplicates

What is that? Are "2"="B" and "3"="C"?