You could replace the C55 reference in the second formula with the C55 formula to reduce this to one formula. However, your result is text, which doesn't sum, and your formula will work only for values in that size range. Here is a way to build a generic formula that will work for any size values and give you numeric results. I'll build it a step at a time so the action is clearer.
You always want to work with the full number that is inside the parentheses. To locate that regardless of the size of the numbers, you can look between the open parenthesis "(" and the subsequent space. The location of the "(" is:
FIND("(",G55)
Finding the subsequent space starts the search at that location, so its location is:
FIND(" ",G55,FIND("(",G55))
You want to extract your number from the middle of a string, so use the MID function:
MID(G55,FIND("(",G55)+1,FIND(" ",G55,FIND("(",G55))-FIND("(",G55)-1)
That extracts from the string in G55, starting in the position after the "(", and including the number of characters in the difference between the two locations (adjusting the count for the position of the delimiter). That gives you the text version of the number. To sum the values, you need to convert it to a number:
=VALUE(MID(G55,FIND("(",G55)+1,FIND(" ",G55,FIND("(",G55))-FIND("(",G55)-1))
Everything in the formula references cell G55 so if the values are in a column, copy the formula down your helper column to get the list of extracted numbers that you can then sum.