Assumed Position: adjustment necessary when using calculator?

[Rumata]

Hello all! 

Great forum here. I've been browsing and learning for a week; as esoteric as it might be these days, it's nice to have a dedicated place for this subject, for people like me that are just learning. 

I have a question I wanted to run by you.  I've done a few manual sight reductions using the tables and a Davis Mark 3 with a bowl of water for an artificial horizon, and been getting LOPs with accuracy within a few miles which I feel is acceptable for a beginner with such a hokey setup ;).  But I've also been using an online sight reduction calculator just to make the practice process faster (yes it's cheating, but who doesn't just want to play with a new toy for a bit?)  I've been using this calculator: 
https://www.celnav.de/sightred.htm

Along with the USNO almanac data.  Seems to work well; again,  LOPs within a few miles.  But I'm curious:  using the tables, it seems (at least with the tables and forms I've been using) necessary to adjust your initial Assumed Position longitude during the conversion to LHA.  This "adjusted" AP longitude is then used in the LOP plotting process.  

So: is it necessary to also adjust the longitude of the Assumed Position when using that online calculator? I'm guessing not, because, well, plotting the LOP using the calculated intercept from the original AP seems to work well, and the calculator doesn't supply a modified AP longitude.  I'm *guessing* that since this is a calculator, it's solving the appropriate formulae using the actual AP, without any modification being driven by the tables. 

Sanity check? Am I right to plot the LOP directly from my original assumed position when using this online calculator? 

Thanks!

Greetings,

A few times I tried to use exact DR longitude, meaning with degrees and minutes , not assumed position longitude, just to see what the difference will it make. It was anti-sanity check, to use interpolation between different pages of Pub.229 to get not a significant difference in the result. Both Tables and calculators are using sin/cos spherical trigonometry formulas. Therefore, I would not expect big difference. Anyway, I think eons-old method of rounding DR longitude to get whole number LHA/t is working. My HP calculator a few times showed me that 27+13=54.3. It is good that I passed my PE test years ago. So I was still able to catch a slight imperfection in the result. So much for calculators.