First, welcome to the club! Hope you have a great time baking along with us. Feel free to jump into our current set of breads or hit any we've already done and add your results to the older threads.
Now, to your questions...
Let's first set up what we mean by 100% in the Baker's Percentage (for those readers who may find this confusing). In this case, the "100%" base amount everything else depends on would be the 50% each whole rye and white flour. Here he uses 1.2 oz of each so 2.4 oz or 68 grams. 222% of that amount is 68 x 2.22 = 151 grams which comes to 5.3 oz, a bit off from his noted 5.5 oz.
If we look at the Metric column, he uses 180 grams of flour, so the starter amount of 200 grams actually is 111% of the original 180 grams. The 222% number in the BP column is therefore not figuring out right, as you've noted.
Why the differences in the home and metric column? Dunno. Perhaps it has to do with larger production volumes not needed in a home setting? Perhaps he left the converting of the larger volume recipes to "Home" amounts to someone with bad math skills? A good editor would probably have caught these glitches, particularly in a recipe book, but then we're talking Wiley so... <shrugs>
In any case, the quantities he has for the home column, 5.5 oz (156 grams) of old starter, 2.4 oz (68 grams) of flour and 3 oz (85 grams) of water end up being a ratio of about 2.3:1:1.25 and these are perfectly acceptable amounts. This will work for a starter and give you, basically a 1 part old starter and 1 part fresh feed. This large-ish amount of old starter means your freshly fed starter has plenty of yeasties to populate and populate/expand the new quantity rapidly.
The Metric column, on the other hand, uses half the Old Starter quantity so it's ratio is more in the 1.1:1:1.25 area or, roughly a 1 part old starter to 2 parts fresh. This too will work fine except with a smaller old starter amount, the yeastie population will take a bit longer to use up all the fresh food. That would then allow for a bit more time between feeds. In a production environment, this may be crucial to have the starter ready and peaking when you need to use it in your schedule of bread production.
Neither are more right than the other. BUT it is a glitch in the numbers. The home column old starter amount, to stick to the 111% percentage should indeed be 2.6 oz (73 grams) and not the current 5.5 oz (155 grams).
My own starter is made at 100% hydration vs Hamelman's preferred 125% and I do a 1:2:2 ratio using 10, 20 and 20 grams for a total of 50 grams of mother starter. Since pretty much all starter based recipes use (in the home version) only ~30g of old starter, my excess of 40 grams per feed is plenty. I don't fret about the 100% vs 125% difference in that 30 grams since that is a mere matter of about 3 grams less water, hardly notable in a 1.5 kg dough batch.