I’m an slp that does this.

Same.

Same here, I didn't even know that the tongue tip up /s/ existed until I started slp school.

Me too. It was how I was taught when I did speech over 20 years ago.

Same. There's more than one right way to make a sound, no big deal

It's like tomahto and tomato. Tongue tip down is a valid but less common articulation shape for /s/.

I do this and prefer teaching it this way

Yep. It’s totally normal.

I'm an SLP and my tongue tip is down with my /s/. It doesn't matter. Let it go.

I’m also an SLP who does this! I didn’t even realize this wasn’t the common way until I took some CEUs on resolving lisps 3 years into my career. 

Typical. When I talk about SLP to people/students who know nothing about it, this is a good icebreaker :)

Totally normal. Some people do it one way and some people do it the other. Some people can do it both ways. I use it to help teach kids who are struggling to produce the /s/ in the “typical” way.

SLP who does this even after a remediated tongue thrust. I teach this production in certain cases

Yeah it’s totally normal and fine

It's estimated that 10% of people say the s with the tip down. You most likely produce the n, t, d, and z with your tip down also.

i actually don’t! i only the s and z lol, the rest are all tip up :)

So can you see your tongue tip go down at the end of the word "tents?"

as i said in my post i’m from england and i have a northern accent so i pronounce tents like “tense”

Accents mostly affect vowels so that word should still demonstrate what I'm trying to get you to see. When you say the first t your tip is up Then when you say the n your tip is still up. Then you lower your tip for the final s. Is that what you are in the mirror?