In reply to:
I'm not sure whether DH support will do it for you or not.
They have made it very clear that they *will not* modify default PHP settings for a user. I think it is great that they *allow* you do do it yourself, as many (most?) won't let you do such a thing.
In reply to:
But there is no harm to send a ticket to them and ask for help. Just tell them you do not want to mess up their servers and please increase the upload limit for you.
There may not be any *harm*, but is an unnecessary and inappropriate request to make of support, and therefore needlessly increases the support queue. It is not reasonable to ask them to change a setting that they have placed in effect for the mutual benefit of all shared server users; if they didn't think that was an appropriate setting, they would not have set it that way in the first place. 
--rlparker