Setting font size for text and tables using styles approach with python-docx library

I am using the python-docx library to create a docx file that contains text and a table right after it. I want to set the text size to 12 and table size to 9 point using styles. But the size of all the text, including the text in the table cells, is set to 12. I know I can use another loop based approach to solve this problem, but I like to use styles, is this possible?

Style approach (it dosen't work):

import random
from docx import Document
from docx.shared import Pt

doc = Document()
normal_style = doc.styles['Normal']
normal_style.font.size = Pt(12)  # SETTING FONT SIZE 12 FOR TEXT
paragraph = doc.add_paragraph("This is some introductory text.", style='Normal')
num_rows = 5
num_cols = 4
table = doc.add_table(rows=num_rows, cols=num_cols)

for row in table.rows:
    for cell in row.cells:
        cell.text = str(random.randint(1, 100))

table.style = 'TableGrid'
table_grid_style = doc.styles['TableGrid']
table_grid_style.font.size = Pt(9)  # SETTING FONT SIZE 9 FOR TABLES!

doc.save('random_table_with_intro_text.docx')

Other loop-based approach that works fine, but I dislike it:

import random
from docx import Document
from docx.shared import Pt

doc = Document()
paragraph = doc.add_paragraph("This is some introductory text.")
run = paragraph.runs[0]
run.font.size = Pt(12)
num_rows = 5
num_cols = 4

table = doc.add_table(rows=num_rows, cols=num_cols)
for row in table.rows:
    for cell in row.cells:
        paragraph = cell.paragraphs[0]
        run = paragraph.add_run(str(random.randint(1, 100)))
        run.font.size = Pt(9)
table.style = 'TableGrid'
doc.save('random_table_with_intro_text.docx')

Also, if I remove the code that adds the text above the table, it works (maybe I'm missing something):

import random
from docx import Document
from docx.shared import Pt

doc = Document()

num_rows = 5
num_cols = 4
table = doc.add_table(rows=num_rows, cols=num_cols)

for row in table.rows:
    for cell in row.cells:
        cell.text = str(random.randint(1, 100))

table.style = 'TableGrid'
table_grid_style = doc.styles['TableGrid']
table_grid_style.font.size = Pt(9)  # SETTING FONT SIZE 9 FOR TABLES!

doc.save('random_table_with_intro_text.docx')