Books Written are Always Normal Quality

Have you tried writing books in a different world? For instance going to a Library or other community lot in another world and writing a book. 

Product: The Sims 4
Platform:PC
Which language are you playing the game in? English
How often does the bug occur? Every time (100%)
What is your current game version number? 1.103.250.1020
What expansions, game packs, and stuff packs do you have installed? All of them
Steps: How can we find the bug ourselves? Write a book (make sure you have a high writing skill, like level 9 or 10)
What happens when the bug occurs? Sims will only produce normal quality books, no excellent quality books
What do you expect to see? A sim with a higher writing skill more likely to write excellent quality books instead of normal
Have you installed any customization with the game, e.g. Custom Content or Mods? Never used.
Did this issue appear after a specific patch or change you made to your system? Neutral/Not Sure 

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One of my sims is a level 10 in writing, yet he seems to only be able to make normal quality books. He's written 14 books in a short time. Of the 14, 2-3 were bestsellers and the rest have been normal. I remember that at a certain point in the writing skill, sims make excellent quality books, like with the painting skill. His wife, who is level 10 in painting, has been making excellent quality paintings with the occasional masterpiece. For some reason, he can only make normal quality books despite maxing out the skill.

To show that his books are normal quality. All 7 of them are normal.

Here is his max level in writing.

I distinctly remember sims with high writing skills writing excellent quality books. Now, my sim is a vampire who has dampened emotions, so he's always in a fine mood, but that shouldn't affect the quality of books at a higher skill. I'm pretty certain it doesn't affect painting qualities. If I am wrong, please let me know. I also don't know when exactly this showed up, as I don't always write books, but I know it was after an update.

My sim was able to create 3 excellent quality books but now he's only writing normal or bestseller quality. I can't finish this aspiration without writing 2 more excellent quality books. 

I've been through this too and it's so frustrating! I've tried everything, but some of them just seem to degrade the quality of the books. Even with maximum skills, he remains on "Normal". Honestly, at this point I'd rather focus on something else than spend time trying to fix this. When I had to write an essay, I used https://essays.edubirdie.com for help, which saved me a lot of time. So maybe I'll just focus on other aspects of the game until the patch comes out. I hope the developers will fix this soon!