- “一般来说，early/low 等于 20-23, mid 等于 24-26, high/upper 等于 27-29, 可是这不是固定的” (see here)
Yes it's fine.
一 = over, across all.
般 = kind, sort.
一般 = general(ly), usual(ly), normal(ly)
As answered by Noir, "一般上" looks a bit weird to me as well, while I'm a native Chinese speaker.
Generally/Usually, we use "一般来说", "一般而言" or "通常来说" in this context (right, here is a best practice for "一般来说") (Chinese for my last sentence) 一般来说，在这种上下文环境里我们使用"一般来说", "一般而言"或者"通常来说"。
"一般上" sounds weird to me. I'd say "一般而言，这个生词是这样用的" or "这个生词一般是这样用的".
The second sentence is fine.
"一般上" is more like Cantonese (that is spoken in the Guangdong province, Hong Kong, and also Malaysia etc). It seldom appears in Mandarin Chinese. If you want to learn the general Chinese, you can forget about that.
The usage in the second example is correct. As stated by other people, it means generally (but may not be always true).