Eh, a few comments:
Salaried East Coast folks are in the office for pretty much as long as folks in the rest of the country if not longer, but time zone differences tend to make it harder for those of us further west to reach them; our workday rhythms are just out of sync. IME when it comes to professionals there is also much more of a "meeting" culture in East coast workplaces, which is why I'm often not able to get them on the phone. They are at work, but not at their desks. I'm always playing phone tag with folks on the East Coast because they almost always call me at times when I am also not at my desk. Long story why, but I don't go right to the office in the am most days; I have to make a work-related stop first that takes about an hour. By the time I get in it is 11 am on the East Coast, when the staggered lunch breaks start. By the time I've settled into my day they are halfway through theirs.
As to salaried vs. non-salaried, yes, no one usually cares if a senior professional leaves the office or moves hours around for convenience, but that's a perk of seniority in most professions that I know of. Most law firms that I am familiar with (DH has been in practice for 23 years) don't cut that kind of slack for new associates, who are very much judged on how much they are SEEN to be in the office working -- it's called "face-time" in that world; making sure that your boss sees your face any time he or she is in the office, no matter what time of day that happens to be.
(I'm nearly 50, and my hours are very flexible, but there is an understanding that although I am salaried and paid for my production rather than my time, I am still obligated to spend a
minimum of 40 hours per week in work-related endeavors. Usually it is more like 60 hours in point of fact, but I do a lot of it somewhere other than in my office.)
As to "tunafish", you tend to see that in places where Tuna was not a traditional part of the diet. No one recognized what "tuna" was when it first turned up on store shelves in the potted meat section, so stores added the "fish" appellation so that it would be explained. Salmon is found in inland areas so it was a recognizable thing where tuna was not.
(Of course, my dad grew up in a fishing village where tuna was a huge part of the catch, but he still didn't know what it was when he first saw cans of it -- because he had always known it to be called Tunny. For years I had no idea what species Mahi-Mahi was for the same reason; it's "dolphin" where I come from; often called "dolphinfish" to differentiate it from the bottlenose dolphin. There are two representations of one on the roof of a hotel at WDW

)
FTR, traditional "sweet tea" is not sweetened with sugar. It is sweetened with simple syrup, which requires first dissolving the sugar in boiling water, cooling the syrup, and THEN adding the mixture to the tea. The flavor is very different when made this way. I know some folks who prefer their tea only slightly sweetened who actually carry a small bottle of sugar syrup just to put in a restaurant's un-sweet tea.
As to "ink pen", what you're missing is that in many parts of the country "pen" and "pin" are homonyms; the words sound exactly the same because of our accents. For that reason, we differentiate the three most common types of device with that name: ink pen, straight pin, and safety pin. The only thing that we call just a "pen" is an enclosure for animals. (If we put a child in an enclosure it's a playpen.)