Hi Brenda! I am not talking about teaching style at all. Jane is absolutely great!!! I am just talking about an exchanging of definitions in two basic structures - blocks and units. Here is a good site to help me explain: https://handwovenmagazine.com/block-weaves-and-unit-weaves/.
There it is stated: "Block weaves are structures in which groups of warp and weft threads can produce two different-looking interlacements, one that we identify as pattern ("figure") and the other as background (think about how you see a rose motif in some overshot drafts on a background of plain weave) ... Some block weaves, however, make the pattern and background interlacements with independently functioning threading and treadling "units". These units all do the same thing as each other to create either the pattern interlacement or the background interlacement, so you can thread many units of the same block next door to each other and weave many in succession ..." So here block weaves have the interlacement or incidental threads and units don't.
Jane on page 2 of her Units, Blocks and Profiles handout states the opposite: "Unit weaves may have rules like... you can't repeat a unit over and over gain because the float will become too long. Or, to prevent a long float you must insert an incidental thread between the units." "With Block weave structures the rules are cleaner, less fussy. Units can be repeated as many tines as you want without having to worry about incidentals..."
I have found, as of yet, no other author's documentation that states block weaves without interlacement (incidental) threads and units having them. I just think I would want to know there is a different, more standardized definition out there, wouldn't you, if you were a student, to avoid confusion for future weaving adventures? Merry Christmas to you too!