Good to hear you are open to trying Python for this! Sometimes you need the right tool for the job. ChatGPT is very capable, but it is just not robust enough for more complex tasks like this.

While you can technically run a restricted version of Python from within ChatGPT, it cannot make API requests, install new packages, etc. For this reason I would highly recommend installing Python on your computer and running it yourself.

I made an example PDF that looks like this one, here is the Python script you can use:

# extract the content from the PDF into a prompt
from thepipe_api import thepipe
prompt = thepipe.extract("doc.pdf")

# Add your instructions to the prompt
prompt  = [{"role": "user", "content": "Using the given document, output the total number of hours worked by the employee. Return your response in valid JSON format with the key 'hours_worked'."}]

# send the prompt to GPT-4 
from openai import OpenAI
openai_client = OpenAI()
response = openai_client.chat.completions.create(
    model = "gpt-4-turbo",
    messages = prompt,
    response_format = {"type": "json_object"}
)

# GPT-4 will return JSON formatted text, since we asked it to. 
# Now, let's extract the hours worked.
import json
response = response.choices[0].message.content
hours_worked = json.loads(response)['hours_worked']

# Define a Function to calculate score based on hours worked
def calculate_score(hours):
    if hours == 0:
        return 0
    elif hours <= 2000:
        return (hours / 2000) * 10
    else:
        return 10

# Run the function on the hours worked we extracted earlier
score = calculate_score(hours_worked)
print(score)

For that PDF, the code outputs

Total score: 7.0

To get it working, you'll need the OpenAI API for GPT4 and The Pipe API for PDF extraction. I should mention that both APIs, like ChatGPT Pro, are paid.

Good luck!