I have issue with tkinter grid manager consistency.
I have specified columnconfigure so left part have 6, then one column is 1 as delimiter and then on right side (keyboard) the width is 3.
As I understand left side should be twice size of right side. But on screen isn’t. The haight have similar problem. All rows are set to rowconfigure=1, but on screen they are not same height.
What I do wrong?
Minimal part of my program to show problem:

#!/usr/bin/env python3
# -*- coding: utf8 -*-

from tkinter import *


#***************************************************************************************************
root = Tk()
root.geometry("1024x600")

tab3=Frame(root,relief=SUNKEN, bd=5 )
tab3.pack(fill=BOTH, expand=True)

#specify column widths
Colwidths=[6,                       6,                      6,                      1,          3,          3,      3]
gui1=[
        [["Doublenline txt",1,1],      ["Doublenline txt",1,1],   ["Doublenline txt",1,1],   ["",1,1],   ["1",1,1],  ["2",1,1],  ["3",1,1]],
        [["145.0",1,1],                 ["133.7",1,1],              ["133.1",1,1],              ["",1,1],   ["4",1,1],  ["5",1,1],  ["6",1,1]],
        [["Doublenline txt",1,1],      ["TwoCelndblLine",1,2],    ["TwoCelndblLine",1,2],    ["",1,1],   ["7",1,1],  ["8",1,1],  ["9",1,1]],
        [["20.5",1,1],                  ["",1,1],                   ["",1,1],                   ["",1,1],   ["X",1,1],  ["0",1,1],  ["OK️",1,1]]
    ]

for i,v in enumerate(Colwidths): tab3.columnconfigure(i, weight=v)

for y,line in enumerate(gui1):
    tab3.rowconfigure(y, weight=1)  #all rows are same height
    for x, (txt,cs,rs) in enumerate(line):
        if txt!="":
            itm=Label(tab3,text=txt, bd=1, relief=SUNKEN, font=("Arial", 30, "bold"),bg='khaki')
            itm.grid(row=y,column=x, columnspan=cs,rowspan=rs, sticky=NSEW)

root.mainloop()

and the bad output:

I was thinking that font is to big and can’t fit into cell. So I remove sticky and try again and got this:

so there are visible space around every item so size shouldn’t be a problem.