This section continues to remain ambiguous but in my opinion section 44AD was introduced for people who do not mainitain books of accounts. So logically such people will have no idea about their actual profits and expenses. They will only have the gross receipts. This is why expenses and depreciation are all disallowed under this section and you are allowed to declare 8% profit on presumptive bases.
Once you avail of this section, you have to avail of this section for the next 5 consecutive years, otherwise it becomes mandatory to undergo audit and maintain books of accounts. This indirectly means that in subsequent years following the year you adopted 44AD, you will be bound to declare 8% profit even if you incurr losses or lower profit.
Given all the data points, I don't think assessee can be forced to declare more than 8% profit since the whole basis of this section is that he does not know his profit margin due to non-maintenance of books of accounts. If assessee is forced to declare actual profits and also not allowed to claim any expenses or depreciation, then the whole intention behind this section falls apart and he would be better off maintaining books of accounts and filing under 44AA which is very difficult for any small businessman to do on his own.