You're right. But I don't agree that you set up the opposite concept between Pinyin and Mandarin. Chinese is both meaning and tone literal symbol. Pinyin is its tone symbol, that is Pinyin is one part of Mandarin. In different zone, there are different tone or accent. We commonly care about Mandarin because it is offical language. Pinyin system has 5 tones. FYI.

There are only 5 tones, but in the context of a sentence these may sound slightly different from the way they sound in isolation, because of the way syllables with different tones follow each other, which part of the sentence is emphasised etc. There is an example on page 46 of Paul Kratochvil's "The Chinese Language Today" (2nd printing, 1970). If you're interested I can post a scan somewhere.

How many tones in Cantonese?

Yes,there are only five tones in Mandarin. (Generally speaking, it is four, cuz we don't really count the neutral tone.) These are the examples from Wikipedia, taking "ma" as an example: 妈／媽(mā) "mother"—high level 麻(má) "linen" or "numb"—high rising 马／馬(mǎ) "horse"—low falling-rising 骂／罵(mà) "scold"—high falling 吗／嗎(ma) "question particle"—neutral Changing tones can lead to misunderstandings, or people cannot understand whar your are saying. Making a new tone other than these five tones just doesn't make any sense.