What hoster is that? Many cheap hosters tend to oversell node's computing power so you can't really trust those usage numbers. In case of virtual cores, when you don't control the node, you never know what cpu power you got any given moment, I have seen that many times back in the day. They tell you that you have, say, 3x2.40GHz while your real cpu power might be an equivalent of e.g. 3x500MHz when the node is very busy (some hours of the day). Used to have lots of cpu spikes while they were not really caused by the Tea*Speak itself. I suspect that it could be similar in your case.
All of those problems ended when I moved to dedicated. Thus, in my opinion the only cpu spike report that makes sense is the one coming from genuine machine with real cpu power.