I did a littlelittlelittle investigating and MyBookie seems to be dualing (based on my sample size of one line).
<TABLE cellSpacing=1 width="100%" border=0><TBODY><TR bgColor=#cc0000><TD noWrap bgColor=#666666>
</TD><TD bgColor=#cc0000><TABLE height=28 cellSpacing=0 cellPadding=0 width=41 align=center border=0><TBODY><TR><TD noWrap height=14>
137u-105
</TD></TR><TR><TD noWrap height=14>
14-105
</TD></TR></TBODY></TABLE></TD><TD class=booksWhite><TABLE height=28 cellSpacing=0 cellPadding=0 width=66 align=center border=0><TBODY><TR><TD noWrap height=14>
137.5u-107
</TD></TR><TR><TD noWrap height=14>
13-106
</TD></TR></TBODY></TABLE></TD><TD class=booksWhite><TABLE height=28 cellSpacing=0 cellPadding=0 width=66 align=center border=0><TBODY><TR><TD noWrap height=14>
n/a
</TD></TR><TR><TD noWrap height=14>
13-110
</TD></TR></TBODY></TABLE></TD><TD class=booksWhite><TABLE height=28 cellSpacing=0 cellPadding=0 width=66 align=center border=0><TBODY><TR><TD noWrap height=14>
n/a
</TD></TR><TR><TD noWrap height=14>
13-110
</TD></TR></TBODY></TABLE></TD><TD class=booksWhite><TABLE height=28 cellSpacing=0 cellPadding=0 width=66 align=center border=0><TBODY><TR><TD noWrap height=14>
137.5u-110
</TD></TR><TR><TD noWrap height=14>
13-110
</TD></TR></TBODY></TABLE></TD><TD class=booksWhite><TABLE height=28 cellSpacing=0 cellPadding=0 width=66 align=center border=0><TBODY><TR><TD noWrap height=14>
n/a
</TD></TR><TR><TD noWrap height=14>
13-110
</TD></TR></TBODY></TABLE></TD><TD class=booksWhite><TABLE height=28 cellSpacing=0 cellPadding=0 width=66 align=center border=0><TBODY><TR><TD noWrap height=14>
n/a
</TD></TR><TR><TD noWrap height=14>
13-107
</TD></TR></TBODY></TABLE></TD><TD class=booksWhite><TABLE height=28 cellSpacing=0 cellPadding=0 width=66 align=center border=0><TBODY><TR><TD noWrap height=14>
n/a
</TD></TR><TR><TD noWrap height=14>
13-107
</TD></TR></TBODY></TABLE></TD><TD class=booksWhite><TABLE height=28 cellSpacing=0 cellPadding=0 width=66 align=center border=0><TBODY><TR><TD noWrap height=14>
138u-110
</TD></TR><TR><TD noWrap height=14>
13-110
</TD></TR></TBODY></TABLE></TD><TD class=booksWhite><TABLE height=28 cellSpacing=0 cellPadding=0 width=66 align=center border=0><TBODY><TR><TD noWrap height=14>
n/a
</TD></TR><TR><TD noWrap height=14>
n/a
</TD></TR></TBODY></TABLE></TD><TD class=booksWhite><TABLE height=28 cellSpacing=0 cellPadding=0 width=66 align=center border=0><TBODY><TR><TD noWrap height=14>
n/a
</TD></TR><TR><TD noWrap height=14>
13-110
</TD></TR></TBODY></TABLE></TD><TD class=booksWhite><TABLE height=28 cellSpacing=0 cellPadding=0 width=66 align=center border=0><TBODY><TR><TD noWrap height=14>
138.5u-110
</TD></TR><TR><TD noWrap height=14>
12-110
</TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>
Way downdowndown there on the right Mybookie has -12 on the RX Lines, this is predictably because they have -12 in their feed. I logged into to my "must call in all plays sir" account and I see a -13 .. hmmm.
So I recheck the feed and it's -12.
So I logout and login in as guest/guest and it's -12.
Seems like dualing to me, but I some bug could be at play (though I suspect not).