I rec'd an email you replied but it's not here, and the email didn't include your entire reply, the last words were "I was". To answer what I did see; I do that on all my cars, which is currently a '16 E550. I had a '13 E350 too which got the same treatment. A CLK320, 190E, ML320, ML55 plus whatever misc other vehicles and stuff like generators. I've done this since my first car at 16 because thicker oil simply protects better period. If it says 10W30 it's just 10wt with thickeners, not 30wt. If I lived where it was so cold that thicker oil was an issue I'd buy a block heater or pre-oiler instead (I want a pre-oiler anyway btw). Plus Lucas sticks to parts better so cold starts are less an issue. How much it helps I can't say, but it does help. If your eng is freezing cold then probably not such a good idea but not a concern for me.
I can't say how well my thicker mix-o-stuff works but I firmly believe it works much better than what virtually everyone else has in their cars. I'm also much harder on engines than most so I especially feel the need for it. At some point oil could be too thick but I don't believe I'm anywhere near that point. It may drop into the low 30's at night in the worst part of winter but the eng doesn't. Last time I bothered to look at the eng temp on a cold ass morning it was >60 at 5am. I forget exactly but the point is it holds heat for a long time so when I see oil temp charts I'm feel I'm more than fine. So you just have to decide for yourself what your needs are, and if you want to add stuff like Zinc, Phosphorus, Moly, Boron, Tungsten or whatever bends your barb. I actually have all of them except Moly in mine. Why? Because I can

You might also consider Amsoil. It's better stuff and arguably the best oil period. I buy direct which requires an account that's like $10 for 6 months. That nets a good discount (25%?) + free shipping. I buy plenty of oil before that time runs out and it'll last me several years. They have all kinds of other cool stuff too. The Signature Series Amsoil is more expensive than the typical oil they sell so you can save a couple bucks a qt getting the regular stuff. Not sure what the difference is but the claimed miles per change is like 25k for the Signature. Not that I'd do that but I feel at 10-12k I'm in better shape than if I had the regular 12k oil. I think I read the difference was additives to resist acidity? Or that plus other stuff? I dunno but it makes me feel better using it.
So this last time I bought Signature Series 10W-30 and Dominator SAE 60. Then some syn Lucas from Walmart. I used 1qt of Lucas but I don't really know what the best % mix is for my eng and one seemed reasonable. If I used two then I'd feel like I should subtract one 60wt, but who knows. So again more of a warm fuzzy thing but it would be interesting to see data on different ratios of Lucas to make a better decision.
My RV generator I just filled got the same mix of oils but no additives (yet). My friend used cheapo dino oil in his gen and it seized. It had some good hours on it but I feel it would still be running if it had my mix. I also use a magnet to catch iron the filter misses, or in the gens case it has no filter so even more important. Just stick the biggest and most powerful neodymium mag that fits on the end of the drain plug. If you don't have an alum pan then the magnet may decide to stick to that and you have problem, so in those cases I use JB Weld. On my truck I actually installed a huge drain plug (1" NPT) which of course I had to put a huge magnet on

It catches a lot of metal which is so fine you can't feel it so mixed with the oil it's basically thick ferro fluid in a big black spiky ball on the magnet. People assume filters catch everything but they're mistaken. In fact, all the engines I've worked on have a filter bypass so much, possibly most, of the oil is not filtered at all! I plugged the bypass in my truck because I just can't imagine not. I assume these cars have them too but I'm not taking it apart for that. If it wasn't for the magnet I'd likely devise a super filter to manually clean the oil now and then. I hear some people do that via an auxiliary filter using a small line that taps off the oil galley and dumps back to the eng somewhere so it's slowly working all the time. One guy told me he did that using a roll of toilet paper as a filter element, which he did decades ago in his offroad racing days. Seems like the fibers would start clogging the main filter but maybe they don't shed in oil. He probably used Scott brand which if you've had it you know what I mean. Meanwhile I've been eyeballing the 1 micron filters I use in my RO water filter setup. I have all the other parts including a powerful little elect pump. Now for the next few few days part of my brain will be trying to talk the rest of it into making said setup. It's also telling me to find some kind of filter material to put around my MB filter. Not the whole thing obviously, but like a 1" ring around it or maybe just a square patch. So >99% of the oil would take the easier path via the main filter but it would slowly catch stuff...
As you can see I spend way too much time thinking about stuff that very few others care about...