If you account for the additional volume when adding honey in steps, you can get pretty close on ABV estimates. However, the incremental additions of honey, often referred to as "step-feeding" can produce harsh flavors from sudden osmotic stress of the yeast. It can sometimes push yeast past their usual alcohol tolerance, which can be useful, but I prefer to avoid the harshness.
In a 5 gallon batch, the yeast will have no trouble with 10 pounds of honey, nor with 15 or 16 pounds (for most yeast). If you get up to 17-18+ pounds in a 5 gallon batch you'll be seeing gravity close to 1.130 and at that level, the osmotic pressure really starts making things more difficult for the yeast. When you do high gravity fermentations, it becomes really important to manage the fermentation well. Pitching a higher mass of yeast (like 2 grams per gallon), proper staggered nutrition, aeration, temperature and pH management can all be important to have fermentation reach completion. However it is still quite possible to have excellent results even with starting gravities of 1.150 (about 21 pounds).
For some of the super-high gravity Polish style meads, you do need to avoid mixing in all the honey at once or you'll get a stuck fermentation, but were talking about 30 pounds of honey in a 5 gallon batch.
In general, I'd say no, it isn't wiser to add the honey with subsequent rackings.