It looks like ldow() function doesn't perform properly. It always returns same result as dow().

Zorro version 1.44
Here my code:

function run()
{
set(PLOTNOW);
PlotScale = 8;
PlotWidth = 2000;
ColorEquity=0;
ColorDD=0;
BarPeriod=60;
LookBack=200;
StartDate=20150805;
EndDate=20150807;
PlotDate=20150805;
asset("EURUSD");
vars L =series(priceLow());
vars H=series(priceHigh());
vars L1 =series(L[0]-0.0005);
vars H1=series(H[0]+0.0005);

if (ltod(ET)>=0 && ltod(ET)<1200) plot("loc",H,DOT,RED);
if (tod()>=0 && tod()<1200) plot("utc",L,DOT,GREEN);
// comment 2 rows above and uncomment 2 rows below to get second image
//if (ldow(ET)==4) plot("locW",H1,DOT,RED);
//if (dow(0)==4) plot("utcW",L1,DOT,GREEN);

}

There is difference in 4 hours between local time (ET) and UTC as it's shown in fig. 1.
Obviously, that for UTC a new day of week also has to start on 4 hours (bars) before local time.
However, as it can be seen in fig. 2 it isn't the case.
Maybe I'm doing something wrong?

You're right, there seems to be something wrong with ldow(). We'll check and fix that for the next update.