s_random_opt_group::apply, logic of choosing an option in slots from item_randomopt_group

[ptrs810812]

	// Apply Must options
	for( size_t i = 0; i < this->slots.size(); i++ ){
		// Try to apply an entry
		for( size_t j = 0, max = this->slots[static_cast<uint16>(i)].size() * 3; j < max; j++ ){
			std::shared_ptr<s_random_opt_group_entry> option = util::vector_random( this->slots[static_cast<uint16>(i)] );

			if ( rnd_chance<uint16>(option->chance, 10000) ) {
				apply_sub( item.option[i], option );
				break;
			}
		}

		// If no entry was applied, assign one
		if( item.option[i].id == 0 ){
			std::shared_ptr<s_random_opt_group_entry> option = util::vector_random( this->slots[static_cast<uint16>(i)] );

			// Apply an entry without checking the chance
			apply_sub( item.option[i], option );
		}
	}

Here for must options.

The implementation choose to equally choose from options from slot, then do the chance check.

I think this might not be logical if the there is a big difference for the chance in each option

Another question is that what is the *3 for? Is it just for increasing the probability to pass chance check?

I wonder if this is to follow official logic.