Rounding issue in Woocommerce prices calculations

Question

I'm having an issue when trying to do some calculations within Woocommerce, and it looks like I'm getting a floating-point precision error. I.e: my end sum is 448.99, but actually I need my sum to be 449.00.

Let's take a look at how I arrive to this calculation:

First I save prices of my currently selected variations in an array

$regular_price_array[$variation_key] = (float)get_post_meta($selected_variation_ids[$variation_key]['variation_id'], '_regular_price', true);

Result:

array(6) { [64]=> float(74) [65]=> float(99) [66]=> float(89) [67]=> float(89) [68]=> float(59) [69]=> float(149) }

Then I save my discounts in an array:

$variation_discount_array[$discount_key] = (float)$selected_variation_ids[$discount_key]['discount'];

Result:

array(6) { [0]=> float(19.66) [1]=> float(19.68) [2]=> float(19.68) [3]=> float(19.68) [4]=> float(19.68) [5]=> float(19.68) }

Then I try to do a basic calculation of PRICE * (1 - DISCOUNT/100), then add up each of these prices. This is where the problem happens, due to PHP's floating point precision I think.

$discount_variation_price[$innerKey] = $reg_prices * number_format((1 - $discount/100),4);

Result:

array(6) { [64]=> float(59.4368) [65]=> float(79.5168) [66]=> float(71.4848) [67]=> float(71.4848) [68]=> float(47.3888) [69]=> float(119.6768) } 

If you were to do the math yourself just on the first one you would see the issue. You end up getting ~59.45(which makes up for that last cent), but of course it wouldn't just work like that.

I've tried using bcmath() but on my installation I'm getting an error that this function is undefined and can't find much about it so I'm assuming it's uncommon to use this function in a WordPress website.

All that being said, I'm not exactly well-versed on this particular subject, so I'm wondering what's my best course of action to actually get the sum I need? I'm utterly stumped! Thanks!

Note: the (float) is type-cast here, but before if I didn't type cast it only the discount would be a float and the price would be string. The error still remained though, and I thought maybe changing both to a float would help. This had no impact.